Class 10 · Science · Chapter 6: Control and Coordination
Bihar Board · NCERT · CBSE
All 80 objective questions (MCQ) of this chapter — solve first, then tap “Show answer”. Each question shows its source label: «BSEB 2025 · board paper» = verified from the official board paper; «Board-style (practice)» = Study With Me's own practice questions.
← Chapter 6: Control and Coordination — full notes, video, questions
Which receptors detect smell?
Correct answer: (B) Olfactory receptors
Olfactory receptors detect smell. Gustatory receptors are on the tongue.
Along which path does the electrical impulse travel in a neuron?
Correct answer: (B) Dendrite → cell body → axon
The impulse goes from the dendrite through the cell body to the axon.
Where is the arc completed that pulls the hand off a flame at once?
Correct answer: (B) In the spinal cord
The reflex arc is formed in the spinal cord.
Who keeps the balance and posture of the body?
Correct answer: (B) Cerebellum
The cerebellum keeps posture and balance.
The extra arrangement that protects the brain from shocks is —
Correct answer: (B) A fluid-filled wrapping
The brain is in a bony box and the fluid soaks up a shock.
How does a touch-me-not leaf move when touched?
Correct answer: (B) By a change of water in the cells
The cell swells or shrinks as water rises or falls.
A tendril coils on a support because —
Correct answer: (B) Growth stays slow on the side against the support
The difference between slow and fast growth turns the tendril around.
What is the main conclusion of Activity 6.2?
Correct answer: (B) New growth takes its direction from the light
The old part stays as it was. New growth is toward the light or away from it.
Growth of a pollen tube toward an ovule is an example of —
Correct answer: (B) Chemotropism
This is chemotropism.
The hormone that bends a shoot toward light is —
Correct answer: (B) Auxin
Auxin makes the shaded cells longer.
Like auxin, the work of gibberellin is linked with what?
Correct answer: (B) Growth of the stem
Gibberellins help the stem to grow.
Which gland makes insulin?
Correct answer: (C) Pancreas
The pancreas makes insulin.
What does the pancreas do when sugar in the blood rises?
Correct answer: (B) It makes more insulin
More insulin brings the sugar down. When the sugar falls, secretion is reduced.
The main centre of memory is—
Correct answer: (D) Cerebrum
Thinking, memory and voluntary actions are the work of the cerebrum, the main part of the fore-brain (lesson 3, Fig. 6.3).
The downward growth of roots is called—
Correct answer: (D) Geotropism
Roots grow down in the direction of gravity — geotropism (lesson 5, Fig. 6.6). The shoot grows up, against gravity.
Oestrogen is secreted by—
Correct answer: (C) Ovary
Oestrogen comes from the ovary and controls the development of female sex organs and the menstrual cycle (lesson 7, Table 6.1). The testis secretes testosterone.
Which of the following is a plant hormone?
Correct answer: (D) Cytokinin
Cytokinin is a plant hormone — it promotes cell division (lesson 6). The other three are animal hormones. This is also NCERT exercise Q1.
The fruit-ripening hormone is—
Correct answer: (C) Ethylene
Ethylene is a gaseous plant hormone that ripens fruits. NCERT names auxin, gibberellins, cytokinins and abscisic acid; this board question asks about ethylene separately (lesson 6).
The number of cranial nerves in humans is—
Correct answer: (A) 12 pairs
12 pairs of cranial nerves arise from the brain and 31 pairs of spinal nerves from the spinal cord; together they form the peripheral nervous system (lesson 3).
Blood pressure is controlled by—
Correct answer: (C) Adrenal
Adrenaline from the adrenal gland makes the heart beat faster and contracts muscles around small arteries — blood pressure rises (lesson 7). (Among involuntary controls the medulla also looks after blood pressure — lesson 3.)
Receptors on the tongue that detect taste are called—
Correct answer: (B) Gustatory receptors
Book: gustatory receptors detect taste on the tongue; olfactory receptors detect smell in the nose.
The correct path of an electrical impulse in a neuron is—
Correct answer: (B) dendrite → cell body → axon → nerve ending
Book: the impulse starts at the dendrite, passes through the cell body and travels along the axon to its end.
Where are reflex arcs formed?
Correct answer: (B) In the spinal cord
Book: reflex arcs are formed in the spinal cord, where sensory and motor nerves meet.
Involuntary actions such as salivation, vomiting and blood pressure are controlled by—
Correct answer: (C) medulla in the hind-brain
Book: blood pressure, salivation and vomiting are controlled by the medulla in the hind-brain.
The central nervous system is made of—
Correct answer: (A) the brain and the spinal cord
Book: brain and spinal cord = central nervous system; cranial and spinal nerves = peripheral nervous system.
The spinal cord is protected by—
Correct answer: (B) the vertebral column (backbone)
Book: the brain sits in a bony box (skull) inside a fluid-filled balloon; the spinal cord is protected by the vertebral column.
How does a muscle cell shorten?
Correct answer: (B) By special proteins changing their shape and arrangement
Book: special proteins in muscle cells change their shape and arrangement in response to a nerve impulse, shortening the muscle.
The leaves of the sensitive plant fold on touch because—
Correct answer: (B) the cells change shape by changing the amount of water
Book: this movement is not growth — cells swell or shrink by changing the amount of water in them.
The growth of pollen tubes towards ovules is an example of—
Correct answer: (C) chemotropism
Book: pollen tubes growing towards ovules is an example of chemotropism.
The plant hormone that inhibits growth is—
Correct answer: (D) abscisic acid
Book: abscisic acid inhibits growth; its effects include wilting of leaves.
Insulin is secreted by which gland?
Correct answer: (C) Pancreas
Book: the pancreas makes insulin, which regulates blood sugar.
A deficiency of growth hormone in childhood leads to—
Correct answer: (B) dwarfism
Book: a deficiency of growth hormone (from the pituitary) in childhood leads to dwarfism.
The part of a neuron where information is acquired (the impulse is set off)—
Correct answer: (B) Dendrite
Book: information is acquired at the end of the dendritic tip of a nerve cell, where the electrical impulse is set off.
Walking in a straight line, riding a bicycle, picking up a pencil — the precision of these voluntary actions comes from the—
Correct answer: (B) Cerebellum
Book: the precision of voluntary actions and the balance of the body are controlled by the cerebellum.
Which of the following is a plant hormone?
Correct answer: (D) Cytokinin
Cytokinin — a plant hormone that promotes cell division. The other three are animal hormones.
The gap between two neurons is called a
Correct answer: (B) synapse
The gap between two neurons is the synapse; chemicals carry the impulse across it.
The brain is responsible for
Correct answer: (D) all of the above
Thinking — fore-brain; heart beat/blood pressure — medulla; balance — cerebellum. So all of the above.
The gap between two neurons is called —
Correct answer: (B) Synapse
A synapse is the gap between two neurons.
Which of the following is a plant hormone?
Correct answer: (D) Cytokinin
Cytokinin is a plant hormone and promotes division.
The brain is responsible for —
Correct answer: (D) All of these
Thinking is the fore-brain, the involuntary heartbeat the medulla, balance the cerebellum.
Goitre is linked with a shortage of what?
Correct answer: (B) Iodine
Without iodine thyroxin is not made and goitre can occur.
Bending of the shoot toward light is called —
Correct answer: (B) Phototropism
Bending of the shoot toward light is phototropism.
Blood sugar is lowered by —
Correct answer: (C) Insulin
Insulin from the pancreas lowers blood sugar.
An example of a voluntary action is —
Correct answer: (C) Moving a chair
Moving a chair is done after thinking. Vomiting and the pupil are reflex or involuntary.
Abscisic acid —
Correct answer: (B) Stops growth
Abscisic acid stops growth and leaves may wilt.
Testosterone is made in the —
Correct answer: (B) Testes
The testes make testosterone.
Movement of the touch-me-not differs from bending toward light because —
Correct answer: (A) It does not involve growth
The leaf moves by water, not by growth. The shoot moves by growth.
Releasing hormones stimulate which gland?
Correct answer: (B) The pituitary
Releasing hormones stimulate the pituitary to release hormones.
Downward growth of the root is —
Correct answer: (B) Geotropism
Downward growth of the root is geotropism.
How does a muscle cell become shorter after an impulse?
Correct answer: (B) By special proteins changing shape
Special proteins change their shape and arrangement, so the cell becomes shorter.
When light comes from one side, auxin is greater —
Correct answer: (B) On the shady side
Auxin moves to the shady side and those cells grow longer.
Pulling the hand away at once on touching a hot object is which kind of action?
Correct answer: (B) Reflex
An immediate response without thinking = reflex action; the arc is formed in the spinal cord.
The longest part of a neuron is the—
Correct answer: (C) Axon
The impulse travels from the cell body along the axon to the end; it is the longest part.
Where are olfactory receptors found?
Correct answer: (B) In the nose
Olfactory receptors in the nose detect smell; gustatory receptors are on the tongue.
The main thinking part of the brain is the—
Correct answer: (A) Fore-brain
The fore-brain is the main thinking part; it also has the centres for sight, hearing and smell.
Where do cranial nerves arise from?
Correct answer: (B) The brain
Cranial nerves arise from the brain and spinal nerves from the spinal cord; together they form the peripheral nervous system.
Spinal nerves arise from the—
Correct answer: (A) Spinal cord
Spinal nerves arise from the spinal cord.
The hormone that helps the growth of the stem is—
Correct answer: (B) Gibberellin
Gibberellins help stem growth; insulin and thyroxin are animal hormones.
Wilting of leaves is linked with which hormone?
Correct answer: (C) Abscisic acid
Abscisic acid inhibits growth and is linked with the wilting of leaves.
A pea tendril coils around a support. This is a response to which stimulus?
Correct answer: (B) Touch
The tendril is sensitive to touch; cells on the side away from the support grow more.
The growth of a root towards water is called—
Correct answer: (C) Hydrotropism
Growth towards water = hydrotropism.
The disease caused by too little insulin is—
Correct answer: (B) Diabetes
Too little insulin → blood sugar rises → diabetes.
Thyroxin regulates—
Correct answer: (A) the metabolism of carbohydrates, proteins and fats
Thyroxin regulates carbohydrate, protein and fat metabolism in the body.
The adrenal gland is located—
Correct answer: (B) on top of the kidney
The adrenal gland sits on top of the kidney (Fig. 6.7).
Hormones reach their target organ through—
Correct answer: (B) blood
Endocrine glands release hormones directly into the blood, which carries them to the target.
Releasing hormones are made by the—
Correct answer: (A) Hypothalamus
The hypothalamus releases releasing hormones that make the pituitary release its hormones.
Under the effect of adrenaline, the heartbeat—
Correct answer: (C) speeds up
Adrenaline makes the heart beat faster so that muscles get more oxygen.
Communication between cells in plants is mainly through—
Correct answer: (B) chemicals (hormones)
Plants have no nervous system; they communicate through chemicals (plant hormones).
Auxin is synthesised at the—
Correct answer: (B) shoot tip
Auxin is made at the shoot tip and helps cells grow longer.
The movement of touch-me-not leaves—
Correct answer: (B) is caused by touch and involves no growth
The touch-me-not moves on touch, with no growth involved.
At a synapse, the message is carried forward by—
Correct answer: (A) chemicals
The impulse releases chemicals at the nerve ending that cross the synapse.
Nervous tissue is made of—
Correct answer: (B) an organised network of neurons
Nervous tissue is an organised network of neurons that carries information as impulses.
When the sugar level in blood rises—
Correct answer: (A) the pancreas makes more insulin
Feedback mechanism: sugar rises → the pancreas makes more insulin; when sugar falls, the secretion is reduced.
A buffalo chewing cud is which kind of movement?
Correct answer: (B) Not caused by growth
Chewing cud is not caused by growth; it is a response that breaks up tough food (sub-lesson 1b).
One limit of electrical impulses is that they—
Correct answer: (B) reach only cells connected by nervous tissue
Impulses reach only connected cells, and a cell must reset before sending the next one.
Under adrenaline, blood flow is reduced to the—
Correct answer: (C) digestive system
Muscles around small arteries contract, so the digestive system and skin get less blood and skeletal muscles more.
Which of the following is involuntary?
Correct answer: (B) Vomiting
Vomiting is involuntary and under the medulla.
Cytokinin is present in greater amount —
Correct answer: (B) In fruits and seeds
Cell division is rapid in fruits and seeds.
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 —
Correct answer: (B) Only the new growth bent in the new direction
New growth changes direction. Turning milky is not the conclusion of this experiment.
A person has a swollen neck and has not eaten iodised salt. The most fitting link is —
Correct answer: (B) Too little thyroxin is being made
Without iodine thyroxin is not made. The thyroid swells and shows goitre.
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