1
Which receptors detect smell?
💡 Hint:
These sit in the nose.
Explanation:
Olfactory receptors detect smell. Gustatory receptors are on the tongue.
Class 10 · Science · Chapter 6 · बिहार बोर्ड (BSEB)CBSE · NCERT 2026-27
Control and Coordination
Control and Coordination
How to use this page:
1. Read — activities 6.1 to 6.4, diagram, worked example, board tip
2. Check — each lesson has its own questions; the number follows the lesson
3. Mastery ★ — all of that lesson correct. Redo the wrong ones
4. Name the reflex-arc SVG in order: receptor → sensory → spinal cord → motor → effector.
In NCERT 2026-27 this is chapter 6. In the older 16-chapter Bihar book this chapter is chapter 7. Progress stays in this browser.
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- 1 Taste, smell and the neuron — Activity 6.1
- 2 The reflex arc
- 3 Parts of the brain and how they are protected
- 4 Two kinds of movement in plants
- 5 Seedlings, direction and carbon dioxide — Activity 6.2
- 6 Plant hormones — growth and a stop
- 7 Animal hormones — Activities 6.3 and 6.4
- Chapter winner — every lesson at mastery ★
🎬 Shorts
This chapter has no Short on the channel yet, so ten empty cards are not shown. The notes, diagrams and checks are complete.
📄 PDF download — notes + answer key
Taste, smell and the neuron — Activity 6.1
स्वाद, गंध और न्यूरॉन — क्रियाकलाप 6.1 · NCERT 6.1 · Activity 6.1
Receptors pick up a changeNotes
News from the surroundings is taken by receptors at the tips of nerve cells. Gustatory receptors on the tongue detect taste. Olfactory receptors in the nose detect smell.
A chemical step at the dendritic tip makes an electrical impulse. It travels from the cell body along the axon. Chemicals leave the axon end, cross the synapse, and start a new impulse in the next cell.
Activity 6.1 — taste sugar with the nose blockedActivity
First put sugar in the mouth. It tastes sweet. Then press the nose between thumb and index finger and taste sugar again. At lunch, block the nose the same way and notice whether the taste opens fully.
The taste often turns dull. A cold does the same, because the smell receptors are not helping. The sweetness of sugar stays on the tongue, but the full identity of a meal needs the nose.
Worked exampleExample
Question: How do we detect the smell of an incense stick?
Answer: Olfactory receptors in the nose detect the smell. From there an impulse travels along a sensory neuron to the fore-brain, where the area for smell sits.
10-second revision
- Gustatory receptors on the tongue, olfactory receptors in the nose
- A blocked nose leaves the taste of food incomplete
- Impulse: dendrite → cell body → axon → synapse
Board tip · BSEBBoard tip
In an objective item the synapse is the gap between two neurons, not the dendrite.
Board tip · CBSEBoard tip
CBSE asks where the impulse becomes a chemical signal — at the axon end, for the next cell.
Check your understandingall correct = mastery ★
2
With the nose blocked, sugar and a meal often do not give their full taste.
Explanation:
True — smell joins in identifying taste. A cold does the same.
3
The gap between two neurons is called a ______.
Explanation:
At the synapse, chemicals start an impulse in the next cell.
4
Along which path does the electrical impulse travel in a neuron?
💡 Hint:
The news arrives at the dendritic tip.
Explanation:
The impulse goes from the dendrite through the cell body to the axon.
5
In Activity 6.1, why does taste change when the nose is blocked?
Model answer (board format)
The full identity of food is built from both taste and smell. With the nose blocked the olfactory receptors cannot work, so the taste seems dull.
Check your answer:
The reflex arc
प्रतिवर्ती चाप · NCERT 6.1.1 · Reflex action
The hand moves before we thinkNotes
Touching a hot object is dangerous. If the brain had to think out an order every time, the burn would already have happened. So the sensory and motor neurons join where they first meet — in the spinal cord.
That join is called a reflex arc. The order is: receptor, sensory neuron, relay neuron in the spinal cord, motor neuron, effector. The news also goes on to the brain, but the order has already left.
Worked exampleExample
Question: The pupil narrows when bright light falls on the eye. Where is this arc made, and what is the role of the brain?
Answer: This is a reflex. Input and output join quickly in the spinal cord. The brain receives the news, but it does not make the narrowing wait.
10-second revision
- The arc is made in the spinal cord, not in the skull
- Order: receptor → sensory → spinal cord → motor → effector
- News reaches the brain; the order leaves the spinal cord
Board tip · BSEBBoard tip
Name the relay neuron in the middle. Do not leave the order unfinished at “spinal cord”.
Board tip · CBSEBoard tip
CBSE asks that the brain is not useless in a reflex — it gets the news, but the spinal cord decides the quick reply.
Check your understandingall correct = mastery ★
1
Where is the arc completed that pulls the hand off a flame at once?
💡 Hint:
Nerves meet in a bundle here.
Explanation:
The reflex arc is formed in the spinal cord.
2
In a reflex the information never reaches the brain.
Explanation:
False — the information also reaches the brain. The quick order leaves the spinal cord.
3
In a reflex arc the muscle works as the ______.
Explanation:
The effector is the organ that gives the response. In this example it is the muscle.
4
Write one difference between a reflex action and moving a chair.
Model answer (board format)
A reflex happens from the spinal cord without thinking, such as pulling the hand from a flame. Moving a chair is voluntary and comes from a decision in the brain.
Check your answer:
Parts of the brain and how they are protected
मस्तिष्क के भाग और उनकी रखवाली · NCERT 6.1.2–6.1.4
Three main parts, two kinds of ordersNotes
The brain and the spinal cord together are the central nervous system. Cranial nerves from the brain and spinal nerves from the spinal cord make the peripheral nervous system.
The fore-brain thinks. Hearing, smell and sight have separate areas, and a centre linked with hunger sits here too. Voluntary muscles, such as those of the leg, get orders from the motor area.
The cerebellum is in the hind-brain. It keeps voluntary movement precise and looks after posture and balance. The medulla looks after involuntary actions such as blood pressure, salivation and vomiting. The mid-brain and the hind-brain handle many involuntary movements.
| Part | Where | Main work |
|---|---|---|
| Fore-brain | Forward part of the skull | Thinking, senses, voluntary movement |
| Cerebellum | Hind-brain | Posture, balance, precision |
| Medulla | Hind-brain | Blood pressure, saliva, vomiting |
Bone, fluid and the protein of muscleNotes
The brain sits in a bony box. A fluid-filled wrapping around it soaks up shocks. The vertebral column protects the spinal cord — the hard bumpy structure along the middle of the back.
After the order arrives, a muscle cell shortens by changing the shape and arrangement of special proteins. A voluntary muscle moves on a thought-out order. An involuntary muscle moves from centres such as the medulla.
Worked exampleExample
Question: Balancing on a bicycle and the mouth watering suddenly — does one part do both?
Answer: No. Balance is the cerebellum. Watering of the mouth without a decision is involuntary and is under the medulla.
10-second revision
- The fore-brain thinks and orders voluntary muscle
- Cerebellum = posture and balance
- Medulla = blood pressure, salivation, vomiting
Board tip · BSEBBoard tip
Do not drag in goitre or insulin in this lesson. The question here asks for the name of the part.
Board tip · CBSEBoard tip
CBSE asks all three together: thinking, the rule of the heartbeat, balance — three different parts of the brain, so “all of these” is the right choice.
Check your understandingall correct = mastery ★
1
Who keeps the balance and posture of the body?
💡 Hint:
A part of the hind-brain, not the medulla.
Explanation:
The cerebellum keeps posture and balance.
2
The medulla controls vomiting.
Explanation:
True — blood pressure, salivation and vomiting are involuntary work of the medulla.
3
The extra arrangement that protects the brain from shocks is —
💡 Hint:
Inside the bony box.
Explanation:
The brain is in a bony box and the fluid soaks up a shock.
4
Precision of voluntary movement is kept by the ______.
Explanation:
Walking in a straight line and picking up a pencil depend on the precision of the cerebellum.
5
Cranial nerves arise from the spinal cord.
Explanation:
False — cranial nerves arise from the brain. Spinal nerves arise from the spinal cord.
6
Which signals can be disrupted by an injury to the spinal cord?
Model answer (board format)
Reflex arcs can break. News going from the body to the brain and orders coming from the brain to the muscles can both stop.
Check your answer:
Two kinds of movement in plants
पौधे की दो तरह की गति · NCERT 6.2 · touch-me-not and tendril
A plant has neither nerves nor musclesNotes
A leaf of the touch-me-not folds and droops as soon as it is touched. This movement involves no growth. The touch is at one place and the movement at another. The news travels cell to cell by electrical-chemical means, but there is no separate conducting tissue as in animals.
Cells of the leaf swell or shrink by changing the amount of water. In an animal muscle, special proteins change shape. Here water changes the shape.
A pea tendril coils around a support when it is touched. Growth stays slow on the side against the support and faster on the side away from it. This movement is caused by growth. Stop the growth and this bending stops.
Worked exampleExample
Question: Write one difference between the leaf of a touch-me-not and a shoot bending toward light.
Answer: The leaf moves at once by a change in water, not by growth. The shoot moves slowly by cells growing longer.
10-second revision
- Touch-me-not: no growth, water in the cells changes
- Tendril: more growth on the side away from the support
- A plant has no separate nervous tissue for messages
Board tip · BSEBBoard tip
Write “immediate” and “by growth” in two separate sentences in the answer.
Board tip · CBSEBoard tip
CBSE asks for a comparison with the movement of a leg — a leg has nerves and proteins, a leaf has a change of water.
Check your understandingall correct = mastery ★
1
How does a touch-me-not leaf move when touched?
💡 Hint:
This movement has no growth.
Explanation:
The cell swells or shrinks as water rises or falls.
2
The coiling of a tendril is caused by growth.
Explanation:
True — cells grow more on the side away from the support.
3
In a plant the news travels cell to cell, but there is no separate ______ tissue.
Explanation:
A plant does not have a nervous system like an animal.
4
A tendril coils on a support because —
💡 Hint:
Faster growth on the far side.
Explanation:
The difference between slow and fast growth turns the tendril around.
5
Why are the touch and the movement not at the same point in a touch-me-not?
Model answer (board format)
The news travels from the point that was touched to the point that moves. Plants send this news by electrical-chemical means, without a separate nervous tissue.
Check your answer:
Seedlings, direction and carbon dioxide — Activity 6.2
अंकुर, दिशा और कार्बन डाइऑक्साइड — क्रियाकलाप 6.2 · NCERT 6.2.2 · Activity 6.2
Do not mix up two different tests on seedsNotes
Germinating seeds give off carbon dioxide in respiration. The previous chapter shows that by turning lime water milky. Activity 6.2 is not that test. The seeds are here so we can see which way the new growth points.
The shoot bends toward light and the root bends away. That is phototropism. Under gravity the root grows down and the shoot grows up — geotropism. Growth toward water is hydrotropism. Growth toward a chemical is chemotropism, such as a pollen tube growing toward an ovule.
Activity 6.2 — conical flask and a windowActivity
Fill a conical flask with water. Cover the mouth with a wire mesh. Keep two or three freshly germinated bean seeds on the mesh. Place the flask in a cardboard box open on one side, with that side toward light from a window.
After two or three days the shoots bend toward the light and the roots bend away. Now turn the flask so the old shoot faces away from the light. After a few days the old part does not change direction. The new growth takes the new direction.
Worked exampleExample
Question: A student treats the water in the flask as lime water and writes that Activity 6.2 proves carbon dioxide. What is the mistake?
Answer: The water in the flask keeps the seeds moist. The conclusion is about direction: new growth toward the light or away from it. Milky lime water belongs to the respiration experiment.
10-second revision
- 6.2 watches direction, not the lime-water test for CO2
- Shoot toward light, root away from light
- The old part does not bend; the new growth does
Board tip · BSEBBoard tip
The question after turning the flask is common. The answer is “new growth”, not “the whole stem swung around”.
Board tip · CBSEBoard tip
If CBSE asks an experiment for hydrotropism, hang germinated seeds in a sieve and keep moist cotton or water below. The root bends toward the water.
Check your understandingall correct = mastery ★
1
What is the main conclusion of Activity 6.2?
💡 Hint:
What changes after the flask is turned.
Explanation:
The old part stays as it was. New growth is toward the light or away from it.
2
Roots bend toward the light.
Explanation:
False — roots bend away from light. The shoot bends toward light.
3
Downward growth of the root under the pull of the earth is called ______.
Explanation:
Shoot up and root down — that is geotropism.
4
Growth of a pollen tube toward an ovule is an example of —
💡 Hint:
Growth toward a chemical.
Explanation:
This is chemotropism.
5
How is phototropism useful to the plant? Answer in one sentence.
Model answer (board format)
The shoot bends toward light and brings the leaves into the light, and the root stays away from light and goes into the soil.
Check your answer:
Plant hormones — growth and a stop
पादप हॉर्मोन — वृद्धि और रोक · NCERT 6.2 · auxin to abscisic acid
Hormones are not made where they actNotes
An electrical impulse reaches only cells joined by nervous tissue, and after one impulse the cell needs time before it can send another. So multicellular bodies also keep a second path: a chemical message.
Plant hormones act away from where they are made and arrive by diffusion. Auxin is made at the shoot tip. If light comes from one side, auxin moves to the shady side and makes those cells longer. The shoot appears to bend toward the light.
Gibberellins also help the stem to grow. Cytokinins promote cell division, so they are present in greater amount in fruits and seeds. Abscisic acid stops growth. Under its effect leaves wilt.
The hormone conclusion of Activity 6.2Activity
In that same flask experiment the shoot bent toward the light because auxin made at the tip collected more on the shady side. The new growth lengthened there. The old part did not bend, because that growth was already finished.
| Hormone | Work |
|---|---|
| Auxin | Cells longer; shoot toward light |
| Gibberellin | Growth of the stem |
| Cytokinin | Cell division; fruits and seeds |
| Abscisic acid | Stops growth; leaves wilt |
Worked exampleExample
Question: How does auxin help a tendril to coil?
Answer: On the side away from the support, auxin makes the cells grow longer. Growth stays less on the side in contact, so the tendril circles the support.
10-second revision
- Auxin on the shady side → cells longer
- Gibberellins grow the stem; cytokinin means division
- Abscisic acid stops growth
Board tip · BSEBBoard tip
Do not write “length of the stem” for cytokinin. Division is its word.
Board tip · CBSEBoard tip
CBSE asks separately which of the four stops growth. Abscisic acid is the only inhibitor.
Check your understandingall correct = mastery ★
1
The hormone that bends a shoot toward light is —
💡 Hint:
It is made at the tip.
Explanation:
Auxin makes the shaded cells longer.
2
Cytokinin promotes cell division.
Explanation:
True — it is present in greater amount in parts of rapid division, such as fruits and seeds.
3
The plant hormone that stops growth is ______.
Explanation:
Abscisic acid stops growth and leaves may wilt.
4
Like auxin, the work of gibberellin is linked with what?
💡 Hint:
Both promote growth.
Explanation:
Gibberellins help the stem to grow.
5
Auxin collects more on the lit side and makes those cells longer.
Explanation:
False — it is greater on the shady side. The longer cells are in the shade, so the bend appears toward the light.
6
What are plant hormones? Write one job of auxin.
Model answer (board format)
They are chemical messages made in one place that coordinate growth and the reply to the surroundings in another place. Auxin bends the shoot toward light by making cells longer on the shady side.
Check your answer:
Animal hormones — Activities 6.3 and 6.4
जंतु हॉर्मोन — क्रियाकलाप 6.3 और 6.4 · NCERT 6.3 · Table 6.1
A second path — endocrine glandsNotes
In a frightening situation the body must get ready either to fight or to run. Nerves alone do not reach every tissue. Adrenaline goes straight from the adrenal gland into the blood. The heart speeds up, skeletal muscles receive more oxygen, blood toward digestion and the skin falls, and breathing increases.
The amount and timing of a hormone are controlled by feedback. If blood sugar rises, the pancreas makes more insulin. If the sugar falls, secretion is reduced. If growth hormone is low, the hypothalamus releases a releasing factor and the pituitary releases growth hormone.
Activity 6.3 — name the glands in the figureActivity
In the figure of endocrine glands, identify the pituitary, thyroid, adrenal, pancreas, testes and ovary. Ask a teacher or a book about a gland that is missing from the table. The hypothalamus stimulates the pituitary to release several hormones.
Activity 6.4 — complete Table 6.1Activity
A blank is either the hormone, the gland or the job. The hormone in the thyroid row is thyroxin. The gland for insulin is the pancreas. The job of the testes is the changes of puberty in boys and the formation of sperms. The hormone of the ovary is oestrogen. Adrenaline prepares the body for an emergency. Releasing hormones come from the hypothalamus.
Iodine is necessary to make thyroxin. A shortage in the food can cause goitre — the neck swells, because the thyroid sits there. A shortage of growth hormone in childhood can cause dwarfism. Around puberty, testosterone in boys and oestrogen in girls change the form of the body.
| Hormone | Gland | Work |
|---|---|---|
| Growth hormone | Pituitary | Growth of the organs |
| Thyroxin | Thyroid | Metabolism and growth; needs iodine |
| Insulin | Pancreas | Lowers blood sugar |
| Testosterone | Testes | Puberty changes in boys |
| Oestrogen | Ovaries | Female organs and the menstrual cycle |
| Adrenaline | Adrenal | Emergency preparation |
Worked exampleExample
Question: Why are some diabetic patients given injections of insulin?
Answer: The pancreas is not making enough insulin. Sugar in the blood rises. The injected insulin brings that sugar down so cells can use it.
10-second revision
- Adrenaline: faster heart, more blood to muscle, faster breathing
- Less iodine → less thyroxin → goitre
- Feedback of insulin depends on blood sugar
Board tip · BSEBBoard tip
Learn the blank cells of the table: thyroxin, pancreas, oestrogen.
Board tip · CBSEBoard tip
CBSE asks iodine and goitre with the reason. Do not stop at “salt is good”. Write both thyroxin and the swelling of the neck.
Check your understandingall correct = mastery ★
1
Which gland makes insulin?
💡 Hint:
Blood sugar is linked with this gland.
Explanation:
The pancreas makes insulin.
2
A copper-T is a hormone of this chapter.
Explanation:
False — a copper-T is not in this chapter. Insulin, thyroxin and adrenaline are hormones.
3
The disease caused by a shortage of iodine is called ______.
Explanation:
In goitre the neck swells, because the thyroid cannot make enough thyroxin.
4
What does the pancreas do when sugar in the blood rises?
💡 Hint:
This is feedback.
Explanation:
More insulin brings the sugar down. When the sugar falls, secretion is reduced.
5
A shortage of growth hormone in childhood can cause dwarfism.
Explanation:
True — the pituitary releases this hormone.
6
What happens to the heart, the blood and breathing when adrenaline is secreted?
Model answer (board format)
The heart beats faster. Contraction of small arteries diverts blood from digestion and the skin toward the skeletal muscles, so the muscles receive more oxygen. Muscles of the diaphragm and the ribs make breathing faster.
Check your answer:
❓ Full question bank — with answers and explanations — 66 questions
Pick a type. The 37 lesson checks are separate — each lesson has as many as its topic needs. All correct earns mastery ★.
BSEB modelpractice · not annual60 tried · 0 correctMultiple choiceMCQ140 tried · 0 correctTrue / falseTrue / false80 tried · 0 correctFill in the blanksFill80 tried · 0 correctMatchMatch20 tried · 0 correctAssertion–reasonAssertion–reason40 tried · 0 correctBalancingBalancing40 tried · 0 correctIdentifyIdentify20 tried · 0 correctShort and longVSA, SA, LA120 tried · 0 correctCBSE-stylenot a PYQ60 tried · 0 correct
No question is marked as a verified past paper. The BSEB set is a model for practice. CBSE items are CBSE-style, not a copy of any year’s paper.
Multiple choice
0/14Pick one option. A wrong try brings a hint.
1
The gap between two neurons is called —
💡 Hint:
Chemicals cross this gap.
Explanation:
A synapse is the gap between two neurons.
2
Which of the following is a plant hormone?
💡 Hint:
The other three are animal hormones.
Explanation:
Cytokinin is a plant hormone and promotes division.
3
The brain is responsible for —
💡 Hint:
Different parts do different jobs.
Explanation:
Thinking is the fore-brain, the involuntary heartbeat the medulla, balance the cerebellum.
4
Goitre is linked with a shortage of what?
💡 Hint:
Thyroxin is made from this.
Explanation:
Without iodine thyroxin is not made and goitre can occur.
5
Bending of the shoot toward light is called —
💡 Hint:
The word for light is in this name.
Explanation:
Bending of the shoot toward light is phototropism.
6
Blood sugar is lowered by —
💡 Hint:
The pancreas.
Explanation:
Insulin from the pancreas lowers blood sugar.
7
An example of a voluntary action is —
💡 Hint:
A decision is involved.
Explanation:
Moving a chair is done after thinking. Vomiting and the pupil are reflex or involuntary.
8
Abscisic acid —
💡 Hint:
The hormone that stops.
Explanation:
Abscisic acid stops growth and leaves may wilt.
9
Testosterone is made in the —
💡 Hint:
It is linked with puberty in boys.
Explanation:
The testes make testosterone.
10
Movement of the touch-me-not differs from bending toward light because —
💡 Hint:
Water falls and rises.
Explanation:
The leaf moves by water, not by growth. The shoot moves by growth.
11
Releasing hormones stimulate which gland?
💡 Hint:
They come from the hypothalamus.
Explanation:
Releasing hormones stimulate the pituitary to release hormones.
12
Downward growth of the root is —
💡 Hint:
The pull of the earth.
Explanation:
Downward growth of the root is geotropism.
13
How does a muscle cell become shorter after an impulse?
💡 Hint:
Recall muscle from Class 9.
Explanation:
Special proteins change their shape and arrangement, so the cell becomes shorter.
14
When light comes from one side, auxin is greater —
💡 Hint:
The longer cells form on that side.
Explanation:
Auxin moves to the shady side and those cells grow longer.
True or false
0/81
Plants have a nervous system like animals.
Explanation:
False — there is neither nervous tissue nor muscle. Messages travel by electrical-chemical means and by hormones.
2
A reflex arc can be formed in the spinal cord.
Explanation:
True — sensory and motor join quickly here.
3
The cerebellum is the centre for vomiting.
Explanation:
False — the medulla looks after vomiting. The cerebellum keeps balance.
4
Adrenaline is secreted straight into the blood.
Explanation:
True — from the adrenal gland, so that many tissues get ready together.
5
Cytokinin is rarely found in fruits and seeds.
Explanation:
False — it is present in greater amount in these parts of rapid division.
6
Secretion of insulin rises and falls with blood sugar.
Explanation:
True — this is feedback.
7
In Activity 6.2 the water in the flask is lime water and turning milky is the conclusion.
Explanation:
False — the water keeps the seeds moist. The conclusion is the direction of new growth. Milky lime water belongs to the respiration experiment.
8
The hypothalamus can release a releasing factor when growth hormone is low.
Explanation:
True — that factor stimulates the pituitary to release growth hormone.
Fill in the blanks
0/81
Receptors of smell are called ______.
💡 Hint:
Olfactory receptors detect smell.
Explanation:
In the nose.
2
The brain, with a fluid-filled wrapping, sits in a box of ______.
💡 Hint:
The skull is a bony box.
Explanation:
A hard guard.
3
Along with auxin, ______ also helps the stem to grow.
💡 Hint:
Gibberellins help the stem to grow.
Explanation:
Both promote growth.
4
The name of the hormone that is short in diabetes is ______.
💡 Hint:
A shortage of insulin raises blood sugar.
Explanation:
The pancreas.
5
The hormone linked with puberty in girls and the menstrual cycle is ______.
💡 Hint:
Oestrogen comes from the ovary.
Explanation:
The ovary.
6
The spinal cord is protected by the ______ column.
💡 Hint:
The vertebral column protects the spinal cord.
Explanation:
The bumpy bone along the middle of the back.
7
Growth of a root toward water is called ______.
💡 Hint:
Hydrotropism is directional growth toward water.
Explanation:
Hydro means water.
8
The emergency hormone ______ comes from the adrenal gland.
💡 Hint:
Adrenaline goes from the adrenal gland into the blood.
Explanation:
It speeds the heart.
Match
0/21
Match the part with its job.
Column B: A. Balance · B. Vomiting · C. Thinking · D. Reflex arc
1. Cerebellum
2. Medulla
3. Fore-brain
4. Spinal cord
Explanation:
Balance is the cerebellum, vomiting the medulla, thinking the fore-brain, the arc the spinal cord.
2
Match the hormone with the gland.
Column B: A. Thyroid · B. Pancreas · C. Adrenal · D. Pituitary
1. Thyroxin
2. Insulin
3. Adrenaline
4. Growth hormone
Explanation:
Thyroxin is the thyroid, insulin the pancreas, adrenaline the adrenal, growth hormone the pituitary.
Assertion–reason
0/4Check both statements, then see whether the reason explains the assertion.
1
Assertion (A): Iodised salt is advisable.
Reason (R): The thyroid needs iodine to make thyroxin.
Explanation:
Both are true and R is the correct explanation of A. A shortage can cause goitre.
2
Assertion (A): The cerebellum keeps the balance of the body.
Reason (R): Both vomiting and balance are the work of the medulla.
Explanation:
A is true. R is false — vomiting belongs to the medulla, balance to the cerebellum.
3
Assertion (A): Auxin is made at the shoot tip.
Reason (R): Cytokinin promotes cell division.
Explanation:
Both are true, but R does not explain A. They are different hormones.
4
Assertion (A): The shoot bends away from light.
Reason (R): Auxin makes cells longer on the shady side.
Explanation:
A is false — the shoot bends toward light. R is true, and that is why the bend appears toward the light.
Balance the equation
0/4This chapter has no chemical equation. All four items below are coefficient practice only. Do not treat them as a result of the chapter.
1
This is coefficient practice, not a chemical result of this chapter. Fill the coefficients for H2 + O2 → H2O.
H2 + O2 → H2O
Explanation: 2H2 + O2 → 2H2O
2
This is coefficient practice, not a result of this chapter. Fill the coefficients for C + O2 → CO2.
C + O2 → CO2
Explanation: C + O2 → CO2
3
This is coefficient practice, not an equation from Control and Coordination. Fill the coefficients for Mg + O2 → MgO.
Mg + O2 → MgO
Explanation: 2Mg + O2 → 2MgO
4
This is coefficient practice, not a reaction of this chapter. Fill the coefficients for N2 + H2 → NH3.
N2 + H2 → NH3
Explanation: N2 + 3H2 → 2NH3
Classify
0/21
Place each name in its class.
Auxin
Insulin
Synapse
Abscisic acid
Explanation:
Auxin and abscisic acid belong to plants. Insulin belongs to animals. A synapse is a nerve junction.
2
Place each movement in its type.
Hand leaving a flame
Moving a chair
Shoot bending toward light
Touch-me-not leaf
Explanation:
Pulling the hand away is a reflex. The chair is voluntary. The shoot bends by growth. The touch-me-not moves by changing water, not by growth.
Very short answer
0/51
What happens at a synapse?
Model answer (board format)
Chemicals leave the axon end, cross the gap and start an electrical impulse in the next neuron.
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2
Where are gustatory receptors?
Model answer (board format)
On the tongue. Olfactory receptors for smell are in the nose.
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3
What is the role of the brain in a reflex action?
Model answer (board format)
The information reaches the brain, but the quick reply has already left by the arc in the spinal cord. The brain does not delay it by thinking.
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4
Write two plant hormones that promote growth.
Model answer (board format)
Auxin and gibberellin. Cytokinin also promotes division. Abscisic acid stops growth.
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5
Why is the use of iodised salt advisable?
Model answer (board format)
Iodine is needed for thyroxin. Thyroxin keeps metabolism fit for growth. A shortage can cause goitre.
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Short answer
0/41
Write two differences between control by nerves and control by hormones.
Model answer (board format)
Nerves send electrical impulses and are fast, but only as far as connected cells. Hormones are slower, travel far by blood or diffusion, and can keep working.
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2
What will you see after turning the flask in Activity 6.2? How will you keep this apart from the carbon dioxide test?
Model answer (board format)
The old shoot stays in its old direction. New growth bends toward the light and the new root bends away. Turning lime water milky is the respiration experiment. The water in this flask is only moisture.
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3
Write three preparations of the body after adrenaline is secreted.
Model answer (board format)
The heart beats faster, skeletal muscles receive more blood, and breathing becomes faster. Blood toward digestion is reduced.
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4
Write the difference between an involuntary action and a reflex action, with one example each.
Model answer (board format)
A reflex is a quick reply to an outside change, such as the hand leaving a flame, and the arc is in the spinal cord. An involuntary action keeps going without our order, such as vomiting or the heartbeat under the medulla.
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Long answer
0/31
How does phototropism occur? Write the role of auxin and the conclusion of Activity 6.2.
Model answer (board format)
Auxin is made at the shoot tip. If light comes from one side, auxin is greater on the shady side and those cells grow longer, so the shoot bends toward the light. Roots bend away from light. After the flask is turned the old part does not bend, and the new growth takes the new direction. This is not the lime-water test for carbon dioxide.
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2
Complete three rows of Table 6.1: thyroxin, insulin, adrenaline. Also write the control by iodine and by blood sugar.
Model answer (board format)
Thyroxin is made by the thyroid and keeps metabolism balanced for growth. Iodine is needed. A shortage causes goitre. Insulin is made by the pancreas and lowers blood sugar. If sugar rises, insulin rises; if it falls, secretion falls. Adrenaline goes from the adrenal gland into the blood and prepares the heart, the oxygen of the muscles and breathing for an emergency.
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3
Explain the order of a reflex arc with the diagram in mind. Why does news still go to the brain if the spinal cord gives the order?
Model answer (board format)
The order is receptor, sensory neuron, relay in the spinal cord, motor neuron, effector muscle. The arc is in the spinal cord so the hand moves before a burn. Thinking uses many impulses and takes time. The news still goes to the brain so that we know afterwards and can understand the situation. The quick protection does not wait for that.
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BSEB model paper · practice
0/6This model set is for practice. It is not a question from an annual examination of any year. Annual questions will be added only when a source page is available.
1
Which of the following is involuntary?
💡 Hint:
The medulla.
Explanation:
Vomiting is involuntary and under the medulla.
2
Cytokinin is present in greater amount —
💡 Hint:
Where division is rapid.
Explanation:
Cell division is rapid in fruits and seeds.
3
The part that keeps balance is the ______.
💡 Hint:
The cerebellum keeps posture and balance.
Explanation:
The hind-brain.
4
Why does a cold come into the talk of Activity 6.1?
Model answer (board format)
In a cold the nose is blocked and the olfactory receptors cannot help. So the taste of food turns dull in the same way as when we eat with the nose pressed shut.
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5
Compare the movement of a touch-me-not and of our leg in three points.
Model answer (board format)
A leg uses a nerve impulse and muscle protein. A touch-me-not has no separate nervous tissue. Cells of the leaf change shape by changing water. Movement of the leg is not growth, and movement of the leaf is not growth either, but the method is different.
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6
Explain the need for control in animals with one example. Why are both nerves and hormones present?
Model answer (board format)
The hand must leave a hot object at once, or there will be a burn. A reflex arc does that quick work. In fear the whole body must get ready, which connected nerves alone cannot do. Adrenaline reaches many organs with the blood. Nerves are fast and limited. Hormones are slower and wide.
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CBSE-style questions
0/6These are competency-based practice questions. They are not a past paper and not a copy of a CBSE paper.
1
A student kept bean seedlings in a cardboard box. After two days the shoot pointed toward the opening. The flask was turned. Over the next days —
💡 Hint:
The old growth is already finished.
Explanation:
New growth changes direction. Turning milky is not the conclusion of this experiment.
2
A person has a swollen neck and has not eaten iodised salt. The most fitting link is —
💡 Hint:
The gland is in the neck.
Explanation:
Without iodine thyroxin is not made. The thyroid swells and shows goitre.
3
Assertion (A): Some diabetic patients are given injections of insulin.
Reason (R): If insulin is not enough, blood sugar rises and causes harm.
Explanation:
Both are true and R is the correct reason.
4
Assertion (A): A touch-me-not leaf droops as soon as it is touched.
Reason (R): For this movement the leaf cells divide and grow longer.
Explanation:
A is true. R is false — this movement does not involve growth. The amount of water changes.
5
A student writes two sentences: “The medulla keeps balance” and “The cerebellum keeps vomiting”. Correct both.
Model answer (board format)
The cerebellum keeps balance and posture. The medulla keeps vomiting, salivation and blood pressure. The student has swapped the two names.
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6
Blood sugar went above a high level and then returned to normal. What would the pancreas have done in between? Why is this called feedback?
Model answer (board format)
As soon as the sugar rises, cells of the pancreas make more insulin. When the sugar falls, secretion is reduced. The result itself reduces the cause, so this is called feedback.
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🏛️ Board exam corner — Bihar Board (BSEB)— CBSE
Switch board with BSEB | CBSE above. The lessons follow the same NCERT chapter.
BSEB model · practiceBoard tip
This page has no verified annual-exam question, because no source page has been added. The model set below is practice in the board pattern.
🏛️ Model questions on one page →
The verified label will be used only when a source page for the question is available.
CBSE-style · competency-based
These are case and assertion-reason practice items. Do not treat them as past CBSE questions.
🔁 Spaced review — today’s questions
Wrong questions return soon; correct ones return after a few days.
🧠 What you learned + equation sheet
What you learned
- The nervous system sends electrical impulses. Hormones are chemical messages and travel by blood or by diffusion.
- Taste receptors sit on the tongue and smell receptors in the nose. A blocked nose keeps the full taste of food from opening up.
- A reflex arc joins in the spinal cord, so the hand moves before a burn.
- The cerebellum keeps posture and balance. The medulla looks after involuntary actions such as vomiting.
- Auxin collects on the shady side and bends the shoot toward light. Abscisic acid stops growth.
- Thyroxin needs iodine. Insulin lowers blood sugar. Adrenaline is the preparation for an emergency.
| What | Keep this |
|---|---|
| Path of an impulse | dendrite → cell body → axon → synapse |
| Reflex arc | receptor → sensory → spinal cord → motor → effector |
| Balance | cerebellum |
| Vomiting, saliva, blood pressure | medulla |
| Phototropism | shoot toward light; root away |
| Insulin | pancreas · blood sugar falls |
The notes are original writing. The textbook was used only for activity order and numbers. “Verified” will be used only on a question that has a source page.