CBSE Class 7 Science Chapter 9: Life Processes in Animals — Assertion & Reason
CBSE Class 7 Science Assertion & Reason
Expert crafted · Instant PDF download · 2026-27
The following Assertion and Reason questions are based on Chapter 9: Life Processes in Animals from the NCERT Class 7 Science textbook Curiosity. Each question has four options — read both the Assertion (A) and Reason (R) carefully before selecting your answer.
How to attempt Assertion & Reason questions:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is NOT the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Assertion & Reason Questions
1
Assertion (A): Nutrition, respiration, excretion, and reproduction are collectively called life processes.
Reason (R): These processes are fundamentally essential for the survival and maintenance of all living beings.
Reason (R): These processes are fundamentally essential for the survival and maintenance of all living beings.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. These basic functions must occur continuously in an organism's body to sustain life, which is why they are termed life processes.
2
Assertion (A): The breaking down of complex food components into simpler forms occurs in a long tube called the alimentary canal.
Reason (R): The alimentary canal starts in the stomach and ends at the small intestine.
Reason (R): The alimentary canal starts in the stomach and ends at the small intestine.
Answer: (c)
A is true, but R is false. The alimentary canal is indeed where digestion happens, but it is a much longer continuous tube that starts at the mouth and ends at the anus.
3
Assertion (A): Chewing a piece of chapati or boiled rice for a long time makes it taste sweet.
Reason (R): Saliva contains a digestive juice that breaks down the starch present in the food into simple sugars.
Reason (R): Saliva contains a digestive juice that breaks down the starch present in the food into simple sugars.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Chapati and rice are rich in starch. As saliva chemically breaks this complex carbohydrate down into sugar during chewing, a sweet taste develops.
4
Assertion (A): Food moves down the food pipe into the stomach solely due to the downward pull of gravity.
Reason (R): The walls of the food pipe gently contract and relax in a wave-like motion to push the food down.
Reason (R): The walls of the food pipe gently contract and relax in a wave-like motion to push the food down.
Answer: (d)
A is false, but R is true. Gravity is not the primary force moving food. It is the continuous contraction and relaxation of the muscular walls of the oesophagus that actively pushes food into the stomach.
5
Assertion (A): The stomach secretes an acid that helps kill many harmful bacteria present in the ingested food.
Reason (R): The acid in the stomach protects the delicate stomach lining from being damaged by the mucus.
Reason (R): The acid in the stomach protects the delicate stomach lining from being damaged by the mucus.
Answer: (c)
A is true, but R is false. The acid does kill bacteria and aids in protein digestion, but it is the mucus that protects the stomach lining from the highly corrosive acid, not the other way around.
6
Assertion (A): The small intestine is the longest part of the alimentary canal, measuring almost 6 metres.
Reason (R): It is called the 'small' intestine because its total length is much shorter than that of the large intestine.
Reason (R): It is called the 'small' intestine because its total length is much shorter than that of the large intestine.
Answer: (c)
A is true, but R is false. The small intestine is indeed very long (around 6 metres). It is called 'small' because of its narrow width (diameter), not its length; the large intestine is shorter but much wider.
7
Assertion (A): Bile secreted by the liver helps in the digestion of fats by breaking them down into tiny droplets.
Reason (R): Bile is strongly acidic in nature and enhances the acidic effect of the food coming from the stomach.
Reason (R): Bile is strongly acidic in nature and enhances the acidic effect of the food coming from the stomach.
Answer: (c)
A is true, but R is false. Bile does break down fats, but it is mildly basic (not acidic) in nature. Its basicity helps neutralise the acidic food moving down from the stomach so that intestinal enzymes can work.
8
Assertion (A): The inner lining of the small intestine has thousands of tiny, finger-like projections.
Reason (R): These projections drastically increase the surface area for the efficient absorption of digested nutrients into the blood.
Reason (R): These projections drastically increase the surface area for the efficient absorption of digested nutrients into the blood.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. These projections allow maximum contact with the digested food, ensuring that nutrients rapidly pass into the bloodstream.
9
Assertion (A): The large intestine absorbs most of the remaining water and some salts from the undigested food.
Reason (R): The final digestion of carbohydrates and proteins is completed in the large intestine before excretion.
Reason (R): The final digestion of carbohydrates and proteins is completed in the large intestine before excretion.
Answer: (c)
A is true, but R is false. The large intestine's main role is water and salt absorption to form solid stool. Digestion of nutrients is already completed in the small intestine.
10
Assertion (A): Cows and buffaloes are called ruminants because they chew their food completely before swallowing it for the first time.
Reason (R): Ruminants bring partially digested food back from their stomach to their mouth for gradual chewing.
Reason (R): Ruminants bring partially digested food back from their stomach to their mouth for gradual chewing.
Answer: (d)
A is false, but R is true. Ruminants initially swallow grass quickly with very little chewing. They later bring this partially digested food (cud) back up to the mouth to chew it thoroughly (rumination).
11
Assertion (A): Birds possess a specialised muscular chamber in their digestive system called a gizzard.
Reason (R): Since birds lack teeth, the contracting walls of the gizzard, often aided by swallowed stones, grind and break down their food.
Reason (R): Since birds lack teeth, the contracting walls of the gizzard, often aided by swallowed stones, grind and break down their food.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The gizzard acts as a mechanical grinder, performing the chewing function that teeth normally would.
12
Assertion (A): It is healthier to breathe through the nose rather than the mouth.
Reason (R): Tiny hair and mucus present inside the nostrils help trap dust and dirt from the inhaled air.
Reason (R): Tiny hair and mucus present inside the nostrils help trap dust and dirt from the inhaled air.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. Breathing through the nose filters the air, ensuring that harmful dust particles do not easily reach the lungs.
13
Assertion (A): During the process of inhalation, the diaphragm moves downwards.
Reason (R): The downward movement of the diaphragm increases the space inside the chest cavity, allowing air to rush into the lungs.
Reason (R): The downward movement of the diaphragm increases the space inside the chest cavity, allowing air to rush into the lungs.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The expansion of the chest cavity creates a vacuum effect that pulls fresh air into the respiratory system.
14
Assertion (A): When exhaled air is blown continuously through a straw into lime water, the liquid turns milky.
Reason (R): Exhaled air contains a higher concentration of carbon dioxide, which reacts with lime water to produce a milky white substance.
Reason (R): Exhaled air contains a higher concentration of carbon dioxide, which reacts with lime water to produce a milky white substance.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. This is the standard chemical test for carbon dioxide, proving that our bodies produce and expel it as a waste product of respiration.
15
Assertion (A): The exchange of oxygen and carbon dioxide takes place across the alveoli of the lungs.
Reason (R): Alveoli have thick, highly muscular walls that physically pump oxygen into the surrounding blood vessels.
Reason (R): Alveoli have thick, highly muscular walls that physically pump oxygen into the surrounding blood vessels.
Answer: (c)
A is true, but R is false. The exchange does happen at the alveoli, but their walls are extremely thin, not thick and muscular. This thinness allows gases to diffuse easily into and out of the blood.
16
Assertion (A): Breathing and respiration are two terms for the exact same biological process.
Reason (R): Breathing is a physical process of inhaling and exhaling, while respiration is a chemical process that breaks down glucose to release energy.
Reason (R): Breathing is a physical process of inhaling and exhaling, while respiration is a chemical process that breaks down glucose to release energy.
Answer: (d)
A is false, but R is true. Breathing is only the mechanical ventilation of the lungs, whereas respiration occurs at the cellular level where oxygen actually reacts with food to create energy.
17
Assertion (A): Fish use specialised structures called gills to breathe underwater.
Reason (R): Gills are richly supplied with blood vessels and facilitate the exchange of gases dissolved in water.
Reason (R): Gills are richly supplied with blood vessels and facilitate the exchange of gases dissolved in water.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The high concentration of blood vessels in the gills allows the fish to efficiently extract dissolved oxygen from the surrounding water.
18
Assertion (A): Adult frogs can use only their lungs for breathing and gas exchange.
Reason (R): Tadpoles breathe through gills, while adult frogs use lungs on land and their moist skin in water for gas exchange.
Reason (R): Tadpoles breathe through gills, while adult frogs use lungs on land and their moist skin in water for gas exchange.
Answer: (d)
A is false, but R is true. Adult frogs do not rely solely on their lungs; their moist skin is a highly active respiratory surface that allows them to breathe while submerged in water.
19
Assertion (A): The circulatory system is responsible for transporting nutrients and oxygen to all parts of the human body.
Reason (R): The heart acts as a pump, pushing blood through blood vessels to deliver these essential substances and carry away waste.
Reason (R): The heart acts as a pump, pushing blood through blood vessels to deliver these essential substances and carry away waste.
Answer: (a)
Both A and R are true, and R is the correct explanation of A. The circulatory system relies on the heart's pumping action to maintain a continuous flow of resources and waste removal throughout the body.
20
Assertion (A): During cellular respiration, glucose reacts with oxygen to produce carbon dioxide, water, and energy.
Reason (R): Respiration only occurs in the bodies of animals, while plants rely solely on photosynthesis for their energy.
Reason (R): Respiration only occurs in the bodies of animals, while plants rely solely on photosynthesis for their energy.
Answer: (c)
A is true, but R is false. While the chemical equation for respiration is correct, respiration occurs in ALL living beings, including plants, which also need to break down glucose to release energy for survival.
❓ Frequently Asked Questions
What is covered in CBSE Class 7 Science Chapter 9 Life Processes in Animals?
This chapter covers all key topics from Life Processes in Animals as per CBSE 2026-27 syllabus.
Is this Assertion & Reason useful for CBSE board exams?
Yes, designed for CBSE Class 7 board exam preparation covering the complete syllabus.
Are these CBSE Class 7 Science Assertion & Reason updated for 2026-27?
Yes, all content at eBookPublisher is updated as per the latest 2026-27 CBSE syllabus.
How many chapters are in CBSE Class 7 Science?
All chapters of CBSE Class 7 Science are covered at eBookPublisher with free Assertion & Reason for each chapter.
Can I study Life Processes in Animals online for free?
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