MCQs, NCERT Chapter Solutions, Q & A - Biology - Class 12 PDF Download

 Page 1


MCQs, NCERT Chapter Solutions, Q & A 
 
Q1: The plant hormone which is essential for cell division is 
(a) Ethylene 
(b) Auxin 
(c) Gibberellin 
(d) Cytokinin 
 
Answer: (d) Cytokinin 
 
 
 
Q2: The activities of the internal organs are controlled by the 
(a) Central Nervous System 
(b) Peripheral Nervous System 
(c) Autonomic Nervous System 
(d) None of these 
 
Answer: (a) Central Nervous System 
 
Q3: The seat of intelligence and voluntary action in the brain is 
(a) Diencephalon 
(b) Cerebrum 
(c) Cerebellum 
(d) Medulla Oblongata 
 
Answer: (b) Cerebrum 
 
Q4: The gap between two neurons is known as ___. 
(a) synapse 
(b) synopsis 
(c) impulse 
(d) synaptic node 
 
Answer: (a) synapse 
 
Q5: Which of the following is a plant hormone?  
(a) Thyroxin 
(b) Cytokinin 
(c) Insulin 
(d) Oestrogen 
 
Answer: (b) Cytokinin 
 
Q6: Tropic movements are 
(a) in response to light 
(b) in response to gravity 
(c) uni-directional 
(d) non-directional 
 
Answer: (c) uni-directional 
 
Q7: Artifical ripening of fruit is carried out by  
(a) Auxins 
(b) Ethylene 
(c) Abscisic acid (ABA) 
Page 2


MCQs, NCERT Chapter Solutions, Q & A 
 
Q1: The plant hormone which is essential for cell division is 
(a) Ethylene 
(b) Auxin 
(c) Gibberellin 
(d) Cytokinin 
 
Answer: (d) Cytokinin 
 
 
 
Q2: The activities of the internal organs are controlled by the 
(a) Central Nervous System 
(b) Peripheral Nervous System 
(c) Autonomic Nervous System 
(d) None of these 
 
Answer: (a) Central Nervous System 
 
Q3: The seat of intelligence and voluntary action in the brain is 
(a) Diencephalon 
(b) Cerebrum 
(c) Cerebellum 
(d) Medulla Oblongata 
 
Answer: (b) Cerebrum 
 
Q4: The gap between two neurons is known as ___. 
(a) synapse 
(b) synopsis 
(c) impulse 
(d) synaptic node 
 
Answer: (a) synapse 
 
Q5: Which of the following is a plant hormone?  
(a) Thyroxin 
(b) Cytokinin 
(c) Insulin 
(d) Oestrogen 
 
Answer: (b) Cytokinin 
 
Q6: Tropic movements are 
(a) in response to light 
(b) in response to gravity 
(c) uni-directional 
(d) non-directional 
 
Answer: (c) uni-directional 
 
Q7: Artifical ripening of fruit is carried out by  
(a) Auxins 
(b) Ethylene 
(c) Abscisic acid (ABA) 
(d) Gibberellins 
 
Answer: (b) Ethylene 
 
Q8: Part of brain that controls respiration, heartbeat and peristalsis is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (d) Medulla 
 
Q9: The brain is responsible for  
(a) thinking.  
(b) regulating the heart beat.  
(c) balancing the body.  
(d) all of the above.  
 
Answer: (d) All of the above. 
 
Q10: Which of the following hormone is released by thyroid? 
(a) Insulin 
(b) Thyroxin 
(c) Trypsin 
(d) Pepsin 
 
Answer: (b) Thyroxin 
 
Q11: Which body organ is surrounded by meninges? 
(a) Heart and Lungs 
(b) Brain & Heart 
(c) Brain and Spinal Cord 
(d) Spinal Cord and Lungs 
 
Answer: (c) Brain and Spinal Cord 
 
Q12: Part of brain that controls muscular co-ordination is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
Q13: Growth of the stem is controlled by  
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
Answer: (a) gibberellin 
 
Q14: Wilting of leaves is caused by which hormone? 
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
Page 3


MCQs, NCERT Chapter Solutions, Q & A 
 
Q1: The plant hormone which is essential for cell division is 
(a) Ethylene 
(b) Auxin 
(c) Gibberellin 
(d) Cytokinin 
 
Answer: (d) Cytokinin 
 
 
 
Q2: The activities of the internal organs are controlled by the 
(a) Central Nervous System 
(b) Peripheral Nervous System 
(c) Autonomic Nervous System 
(d) None of these 
 
Answer: (a) Central Nervous System 
 
Q3: The seat of intelligence and voluntary action in the brain is 
(a) Diencephalon 
(b) Cerebrum 
(c) Cerebellum 
(d) Medulla Oblongata 
 
Answer: (b) Cerebrum 
 
Q4: The gap between two neurons is known as ___. 
(a) synapse 
(b) synopsis 
(c) impulse 
(d) synaptic node 
 
Answer: (a) synapse 
 
Q5: Which of the following is a plant hormone?  
(a) Thyroxin 
(b) Cytokinin 
(c) Insulin 
(d) Oestrogen 
 
Answer: (b) Cytokinin 
 
Q6: Tropic movements are 
(a) in response to light 
(b) in response to gravity 
(c) uni-directional 
(d) non-directional 
 
Answer: (c) uni-directional 
 
Q7: Artifical ripening of fruit is carried out by  
(a) Auxins 
(b) Ethylene 
(c) Abscisic acid (ABA) 
(d) Gibberellins 
 
Answer: (b) Ethylene 
 
Q8: Part of brain that controls respiration, heartbeat and peristalsis is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (d) Medulla 
 
Q9: The brain is responsible for  
(a) thinking.  
(b) regulating the heart beat.  
(c) balancing the body.  
(d) all of the above.  
 
Answer: (d) All of the above. 
 
Q10: Which of the following hormone is released by thyroid? 
(a) Insulin 
(b) Thyroxin 
(c) Trypsin 
(d) Pepsin 
 
Answer: (b) Thyroxin 
 
Q11: Which body organ is surrounded by meninges? 
(a) Heart and Lungs 
(b) Brain & Heart 
(c) Brain and Spinal Cord 
(d) Spinal Cord and Lungs 
 
Answer: (c) Brain and Spinal Cord 
 
Q12: Part of brain that controls muscular co-ordination is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
Q13: Growth of the stem is controlled by  
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
Answer: (a) gibberellin 
 
Q14: Wilting of leaves is caused by which hormone? 
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
 
Answer: (c) abscisic acid 
 
Q15: Which of the following hormones contains iodine?  
(a) adrenaline 
(b) testosterone 
(c) thyroxine 
(d) insulin  
 
Answer: (c) thyroxine 
 
Q16: Which part of brain controls the posture and balance of the body? 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
 
Q17: What is the difference between a reflex action and walking? 
 
Answer: 
Reflex Action Walking 
A reflex action is an automatic and rapid (spontaneous) 
response to a stimulus. 
Walking is a voluntary action.  
It is a spontaneous reaction. Spinal cord is involved in it. 
It is a conscious and deliberate action i.e. it is done after a 
thought is processed by the brain. 
It does not involve any kind of thinking or feeling to control 
the reaction. 
It is the voluntary action that we have acquired through 
learning 
Spinal cord is directly involved in it.  It is directly controlled by hind-brain (cerebellum). 
When a bright light is focussed on your eyes, we 
immediately close it, a knee-jerk are examples of reflex 
action.  
Examples: Walking in a straight line, riding a bicycle, 
picking up a pencil (Voluntary actions and precision 
control)  
 
Q18: Why is a system of control and coordination essential in living organisms? 
 
Answer: Following are the reasons: 
1. Increase the chances of survival by responding to stimuli.  
2. Different body parts function as a single unit  
3. To maintain homeostasis.  
Q19: Fill in the blanks. 
 
(a) _____ is the is the structural and functional unit of the nervous system. 
(b) An automatic response to a stimulus which is not controlled by the brain is called ______. 
(c) Chemical messengers which control and coordinate in plants and animals are called _____.  
(d) The movement of a plant part in the direction of light is called ____. 
(e) ________ is the movement of plant part in response to the availability of water. 
(f) ________ is the movement of plant part in response to the pull of earth’s gravity 
(g) The movement of plant part in response to certain chemicals is called ______. 
Page 4


MCQs, NCERT Chapter Solutions, Q & A 
 
Q1: The plant hormone which is essential for cell division is 
(a) Ethylene 
(b) Auxin 
(c) Gibberellin 
(d) Cytokinin 
 
Answer: (d) Cytokinin 
 
 
 
Q2: The activities of the internal organs are controlled by the 
(a) Central Nervous System 
(b) Peripheral Nervous System 
(c) Autonomic Nervous System 
(d) None of these 
 
Answer: (a) Central Nervous System 
 
Q3: The seat of intelligence and voluntary action in the brain is 
(a) Diencephalon 
(b) Cerebrum 
(c) Cerebellum 
(d) Medulla Oblongata 
 
Answer: (b) Cerebrum 
 
Q4: The gap between two neurons is known as ___. 
(a) synapse 
(b) synopsis 
(c) impulse 
(d) synaptic node 
 
Answer: (a) synapse 
 
Q5: Which of the following is a plant hormone?  
(a) Thyroxin 
(b) Cytokinin 
(c) Insulin 
(d) Oestrogen 
 
Answer: (b) Cytokinin 
 
Q6: Tropic movements are 
(a) in response to light 
(b) in response to gravity 
(c) uni-directional 
(d) non-directional 
 
Answer: (c) uni-directional 
 
Q7: Artifical ripening of fruit is carried out by  
(a) Auxins 
(b) Ethylene 
(c) Abscisic acid (ABA) 
(d) Gibberellins 
 
Answer: (b) Ethylene 
 
Q8: Part of brain that controls respiration, heartbeat and peristalsis is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (d) Medulla 
 
Q9: The brain is responsible for  
(a) thinking.  
(b) regulating the heart beat.  
(c) balancing the body.  
(d) all of the above.  
 
Answer: (d) All of the above. 
 
Q10: Which of the following hormone is released by thyroid? 
(a) Insulin 
(b) Thyroxin 
(c) Trypsin 
(d) Pepsin 
 
Answer: (b) Thyroxin 
 
Q11: Which body organ is surrounded by meninges? 
(a) Heart and Lungs 
(b) Brain & Heart 
(c) Brain and Spinal Cord 
(d) Spinal Cord and Lungs 
 
Answer: (c) Brain and Spinal Cord 
 
Q12: Part of brain that controls muscular co-ordination is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
Q13: Growth of the stem is controlled by  
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
Answer: (a) gibberellin 
 
Q14: Wilting of leaves is caused by which hormone? 
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
 
Answer: (c) abscisic acid 
 
Q15: Which of the following hormones contains iodine?  
(a) adrenaline 
(b) testosterone 
(c) thyroxine 
(d) insulin  
 
Answer: (c) thyroxine 
 
Q16: Which part of brain controls the posture and balance of the body? 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
 
Q17: What is the difference between a reflex action and walking? 
 
Answer: 
Reflex Action Walking 
A reflex action is an automatic and rapid (spontaneous) 
response to a stimulus. 
Walking is a voluntary action.  
It is a spontaneous reaction. Spinal cord is involved in it. 
It is a conscious and deliberate action i.e. it is done after a 
thought is processed by the brain. 
It does not involve any kind of thinking or feeling to control 
the reaction. 
It is the voluntary action that we have acquired through 
learning 
Spinal cord is directly involved in it.  It is directly controlled by hind-brain (cerebellum). 
When a bright light is focussed on your eyes, we 
immediately close it, a knee-jerk are examples of reflex 
action.  
Examples: Walking in a straight line, riding a bicycle, 
picking up a pencil (Voluntary actions and precision 
control)  
 
Q18: Why is a system of control and coordination essential in living organisms? 
 
Answer: Following are the reasons: 
1. Increase the chances of survival by responding to stimuli.  
2. Different body parts function as a single unit  
3. To maintain homeostasis.  
Q19: Fill in the blanks. 
 
(a) _____ is the is the structural and functional unit of the nervous system. 
(b) An automatic response to a stimulus which is not controlled by the brain is called ______. 
(c) Chemical messengers which control and coordinate in plants and animals are called _____.  
(d) The movement of a plant part in the direction of light is called ____. 
(e) ________ is the movement of plant part in response to the availability of water. 
(f) ________ is the movement of plant part in response to the pull of earth’s gravity 
(g) The movement of plant part in response to certain chemicals is called ______. 
(h) _________ is the reflex centre of the brain. 
(i) __________ is a structure associated with both nervous system and endocrine system. 
 
Answer: 
(a) Neuron or Nerve cell 
(b) Reflex Action 
(c) Hormones 
(d) Phototropism 
(e) Hydrotropism 
(f) Geotropism 
(g) Chemotropism 
(h) Medulla Oblongata 
(i) Hypothalmus 
 
Synapse 
(credits:clker.com) 
Q20: What happens at the synapse between two neurons? 
 
Answer: Synapse is a very small gap between the last portion of axon of one neuron and the dendron of 
the other neuron. It acts as a one way valve to transmit impulses. This is one directional flow of impulses 
because the chemicals are produced only on one side of the neuron i.e., the axon’s side. Via axon, the 
impulses travel across the synapse to the dendron of the other neuron. 
 
In toto, synapse performs the following tasks: 
1. It allows the information to pass from one neuron to another.  
2. It ensures the passage of nerve impulse in one direction only.  
3. It helps in information processing by combining the effects of all impulses received.  
Watch the you tube video explaining what is the Synapse structure and how it functions. 
 
 
 
 
 
Q21: Which part of the brain maintains posture and equilibrium of the body? 
 
Answer: Cerebellum. 
 
 
Q22: How do we detect the smell of an agarbatti (incense stick)? 
 
Answer: The fore-brain is the main thinking part of the brain. It has regions which receive sensory 
impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight 
Page 5


MCQs, NCERT Chapter Solutions, Q & A 
 
Q1: The plant hormone which is essential for cell division is 
(a) Ethylene 
(b) Auxin 
(c) Gibberellin 
(d) Cytokinin 
 
Answer: (d) Cytokinin 
 
 
 
Q2: The activities of the internal organs are controlled by the 
(a) Central Nervous System 
(b) Peripheral Nervous System 
(c) Autonomic Nervous System 
(d) None of these 
 
Answer: (a) Central Nervous System 
 
Q3: The seat of intelligence and voluntary action in the brain is 
(a) Diencephalon 
(b) Cerebrum 
(c) Cerebellum 
(d) Medulla Oblongata 
 
Answer: (b) Cerebrum 
 
Q4: The gap between two neurons is known as ___. 
(a) synapse 
(b) synopsis 
(c) impulse 
(d) synaptic node 
 
Answer: (a) synapse 
 
Q5: Which of the following is a plant hormone?  
(a) Thyroxin 
(b) Cytokinin 
(c) Insulin 
(d) Oestrogen 
 
Answer: (b) Cytokinin 
 
Q6: Tropic movements are 
(a) in response to light 
(b) in response to gravity 
(c) uni-directional 
(d) non-directional 
 
Answer: (c) uni-directional 
 
Q7: Artifical ripening of fruit is carried out by  
(a) Auxins 
(b) Ethylene 
(c) Abscisic acid (ABA) 
(d) Gibberellins 
 
Answer: (b) Ethylene 
 
Q8: Part of brain that controls respiration, heartbeat and peristalsis is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (d) Medulla 
 
Q9: The brain is responsible for  
(a) thinking.  
(b) regulating the heart beat.  
(c) balancing the body.  
(d) all of the above.  
 
Answer: (d) All of the above. 
 
Q10: Which of the following hormone is released by thyroid? 
(a) Insulin 
(b) Thyroxin 
(c) Trypsin 
(d) Pepsin 
 
Answer: (b) Thyroxin 
 
Q11: Which body organ is surrounded by meninges? 
(a) Heart and Lungs 
(b) Brain & Heart 
(c) Brain and Spinal Cord 
(d) Spinal Cord and Lungs 
 
Answer: (c) Brain and Spinal Cord 
 
Q12: Part of brain that controls muscular co-ordination is ____. 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
Q13: Growth of the stem is controlled by  
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
Answer: (a) gibberellin 
 
Q14: Wilting of leaves is caused by which hormone? 
(a) gibberellin  
(b) auxin 
(c) abscisic acid  
(d) cytokinin 
 
 
Answer: (c) abscisic acid 
 
Q15: Which of the following hormones contains iodine?  
(a) adrenaline 
(b) testosterone 
(c) thyroxine 
(d) insulin  
 
Answer: (c) thyroxine 
 
Q16: Which part of brain controls the posture and balance of the body? 
(a) Cerebrum 
(b) Cerebellum 
(c) Pons 
(d) Medulla 
 
Answer: (b) Cerebellum 
 
 
Q17: What is the difference between a reflex action and walking? 
 
Answer: 
Reflex Action Walking 
A reflex action is an automatic and rapid (spontaneous) 
response to a stimulus. 
Walking is a voluntary action.  
It is a spontaneous reaction. Spinal cord is involved in it. 
It is a conscious and deliberate action i.e. it is done after a 
thought is processed by the brain. 
It does not involve any kind of thinking or feeling to control 
the reaction. 
It is the voluntary action that we have acquired through 
learning 
Spinal cord is directly involved in it.  It is directly controlled by hind-brain (cerebellum). 
When a bright light is focussed on your eyes, we 
immediately close it, a knee-jerk are examples of reflex 
action.  
Examples: Walking in a straight line, riding a bicycle, 
picking up a pencil (Voluntary actions and precision 
control)  
 
Q18: Why is a system of control and coordination essential in living organisms? 
 
Answer: Following are the reasons: 
1. Increase the chances of survival by responding to stimuli.  
2. Different body parts function as a single unit  
3. To maintain homeostasis.  
Q19: Fill in the blanks. 
 
(a) _____ is the is the structural and functional unit of the nervous system. 
(b) An automatic response to a stimulus which is not controlled by the brain is called ______. 
(c) Chemical messengers which control and coordinate in plants and animals are called _____.  
(d) The movement of a plant part in the direction of light is called ____. 
(e) ________ is the movement of plant part in response to the availability of water. 
(f) ________ is the movement of plant part in response to the pull of earth’s gravity 
(g) The movement of plant part in response to certain chemicals is called ______. 
(h) _________ is the reflex centre of the brain. 
(i) __________ is a structure associated with both nervous system and endocrine system. 
 
Answer: 
(a) Neuron or Nerve cell 
(b) Reflex Action 
(c) Hormones 
(d) Phototropism 
(e) Hydrotropism 
(f) Geotropism 
(g) Chemotropism 
(h) Medulla Oblongata 
(i) Hypothalmus 
 
Synapse 
(credits:clker.com) 
Q20: What happens at the synapse between two neurons? 
 
Answer: Synapse is a very small gap between the last portion of axon of one neuron and the dendron of 
the other neuron. It acts as a one way valve to transmit impulses. This is one directional flow of impulses 
because the chemicals are produced only on one side of the neuron i.e., the axon’s side. Via axon, the 
impulses travel across the synapse to the dendron of the other neuron. 
 
In toto, synapse performs the following tasks: 
1. It allows the information to pass from one neuron to another.  
2. It ensures the passage of nerve impulse in one direction only.  
3. It helps in information processing by combining the effects of all impulses received.  
Watch the you tube video explaining what is the Synapse structure and how it functions. 
 
 
 
 
 
Q21: Which part of the brain maintains posture and equilibrium of the body? 
 
Answer: Cerebellum. 
 
 
Q22: How do we detect the smell of an agarbatti (incense stick)? 
 
Answer: The fore-brain is the main thinking part of the brain. It has regions which receive sensory 
impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight 
and so on. 
Olfactoreceptors (present in nose) send the information about the smell of incense stick to fore-brain. The 
for-brain interprets it along with with information received from other receptors as well as with information 
that is already stored in the brain.  
 
Q23: List the functions performed by Cerebrum. 
 
Answer: The cerebrum performs the following functions: 
1. It governs our mental abilities like thinking, reasoning, learning, memorising etc.  
2. It controls our feelings, emotions and speech.  
3. It controls all involuntary functions.  
Q24: Which is the largest and most prominent part of the brain. 
 
Answer: Cerebrum  
Three regions of Brain 
 
 
Q25: What are the functions of cerebellum? 
 
Answer: 
1. Maintains equilibrium or balance of the body.  
2. Coordinates muscular movement.  
3. Controls posture of the body.  
 
Q26: How brain is protected inside a human body? 
 
Answer: Brain is protected by a bony box called cranium, within which are present 3 layers of fluid-filled 
(called cerebrospinal fluid) membranes (called meninges) for absorbing shock and buoyancy. 
 
Q27: What is the role of the brain in reflex action? 
 
Answer: Brain has no role to play in creation of reflex action response. Instead spinal cord is the control 
centre of a reflex action. In fact brain becomes aware after the reflex arc has been formed.