---
title: "NCERT Solutions Class 7 Science Ch 9 Life Processes in Animals"
url: https://www.swavid.com/science/class/7/chapter/life-processes-in-animals/ncert-solutions
dateModified: 2026-10-07T16:07:32+00:00
---

# NCERT Solutions Class 7 Science Ch 9 Life Processes in Animals

This chapter's questions cover the concepts of human and animal life processes, specifically focusing on nutrition, digestion, respiration, and related experimental investigations.

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## Let Us Enhance Our Learning

### Question 1

*3 marks · Short answer*

Complete the journey of food through the alimentary canal by filling up the boxes with appropriate parts—
Food $\rightarrow$ Mouth $\rightarrow$ $\square$ $\rightarrow$ Stomach $\rightarrow$ $\square$ $\rightarrow$ Anus

**Solution**

1. The food enters the mouth and passes into the food pipe or oesophagus.
2. From the oesophagus, the food goes into the stomach, and then into the small intestine.
3. After the small intestine, the undigested food passes into the large intestine and finally reaches the rectum and anus.

**Answer:** Food $\rightarrow$ Mouth $\rightarrow$ Oesophagus $\rightarrow$ Stomach $\rightarrow$ Small intestine $\rightarrow$ Large intestine $\rightarrow$ Anus

> Common mistake: Forgetting to include the small intestine and large intestine in the proper sequence.

### Question 2

*3 marks · Short answer*

Sahil placed some pieces of chapati in test tube A. Neha placed chewed chapati in test tube B, and Santushti took boiled and mashed potato in test tube C. All of them added a few drops of iodine solution to their test tubes—A, B, and C, respectively. What would be their observations? Give reasons.

**Solution**

1. In test tube A, the pieces of chapati contain starch, so the solution turns blue-black upon adding iodine.
2. In test tube B, the chewed chapati has its starch broken down into simple sugars by saliva, so it shows little or no blue-black colour change.
3. In test tube C, the boiled and mashed potato contains starch, so it turns blue-black with iodine.

**Answer:** Test tube A and C turn blue-black due to the presence of starch, while test tube B does not turn blue-black because saliva has broken down the starch into sugars.

> Common mistake: Confusing the action of saliva on starch with other food components like proteins.

### Question 3

*1 mark · MCQ*

What is the role of the diaphragm in breathing?

- To filter the air
- To produce sound
- To help in inhalation and exhalation
- To absorb oxygen

**Solution**

1. The diaphragm is a dome-shaped muscle below the lungs that moves downwards during inhalation and upwards during exhalation to change chest cavity volume.
2. Therefore, its role is to help in inhalation and exhalation.

**Answer:** (iii) To help in inhalation and exhalation

> Common mistake: Choosing absorption of oxygen, which is the function of alveoli.

### Question 4

*3 marks · Short answer*

Match the following
Name of the part 	 Functions
(i) Nostrils 	 (a) fresh air from outside enters
(ii) Nasal passages 	 (b) exchange of gases occurs
(iii) Windpipe 	 (c) protects lungs
(iv) Alveoli 	 (d) tiny hair and mucus help to trap dust and dirt from the air we breathe
(v) Ribcage 	 (e) air reaches our lungs through this part

**Solution**

1. Match (i) Nostrils with (d) tiny hair and mucus help to trap dust and dirt from the air we breathe.
2. Match (ii) Nasal passages with (a) fresh air from outside enters, (iii) Windpipe with (e) air reaches our lungs through this part, (iv) Alveoli with (b) exchange of gases occurs, and (v) Ribcage with (c) protects lungs.

**Answer:** (i)-(d), (ii)-(a), (iii)-(e), (iv)-(b), (v)-(c)

> Common mistake: Mixing up the functions of nostrils and nasal passages.

### Question 5

*3 marks · Short answer*

Anil claims to his friend Sanvi that respiration and breathing are the same process. What question(s) can Sanvi ask him to make him understand that he is not correct?

**Solution**

1. Sanvi can ask Anil whether breathing is a physical process of moving air in and out, while respiration is a chemical process of breaking down glucose inside cells to release energy.
2. She can ask him if breathing occurs only in the lungs and respiratory tract, whereas respiration occurs inside every cell of the body.
3. She can also ask him if breathing involves just exchanging gases, while respiration produces usable energy, water, and carbon dioxide.

**Answer:** Sanvi can ask Anil about the location of the processes, whether energy is released, and if breathing is a physical process while respiration is a chemical process.

> Common mistake: Treating breathing and respiration as synonymous terms.

### Question 6

*3 marks · Short answer*

Which of the following statements is correct and why?
Anu: We inhale air.
Shanu: We inhale oxygen.
Tanu: We inhale air rich in oxygen.

**Solution**

1. Tanu's statement is correct because the air we inhale is a mixture of various gases, of which oxygen is only a fraction (nearly 21%).
2. Anu's statement is incomplete as it does not specify what air contains.
3. Shanu's statement is incorrect because we do not inhale pure oxygen; we inhale air rich in oxygen.

**Answer:** Tanu's statement is correct because inhaled air is a mixture of gases containing nearly 21% oxygen and not pure oxygen.

> Common mistake: Assuming we inhale 100% pure oxygen.

### Question 7

*3 marks · Short answer*

We often sneeze when we inhale a lot of dust-laden air. What can be possible explanations for this?

**Solution**

1. Inhaled air often contains unwanted particles like dust, smoke, and pollen.
2. When these particles pass through the nasal passages, they irritate the lining of the nose.
3. This irritation triggers a sneeze, which expels these foreign particles forcefully from the nose to bring clean air into the body.

**Answer:** Sneezing is a reflex action triggered by unwanted dust particles irritating the nasal lining, which forcefully expels them to clean the air passage.

> Common mistake: Thinking sneezing is a sign of a disease rather than a normal reflex to clear dust.

### Question 8

*3 marks · Short answer*

Paridhi and Anusha of Grade 7 started running for their morning workout. After they completed their running, they counted their breaths per minute. Anusha was breathing faster than Paridhi. Provide at least two possible explanations for why Anusha was breathing faster than Paridhi.

**Solution**

1. During physical activity like running, the body's demand for energy increases.
2. To meet this increased energy demand, cells require more oxygen, which makes the breathing rate faster.
3. Anusha might have been running faster or with more intensity than Paridhi, or she may have a different level of physical fitness and stamina.

**Answer:** Anusha was breathing faster because heavier physical exertion increases the body's demand for oxygen to release energy, or due to differences in individual fitness levels.

> Common mistake: Stating that breathing faster means taking in less oxygen.

### Question 9

*3 marks · Short answer*

Yadu conducted an experiment to test his idea. He took two test tubes, A and B, and added a pinch of rice flour to the test tubes, half-filled with water and stirred them properly. To test tube B, he added a few drops of saliva. He left the two test tubes for 35–45 min. After that, he added iodine solution into both the test tubes. Experimental results are as shown in Fig. 9.15. What do you think he wants to test?

**Solution**

1. Yadu wants to test the effect of saliva on starch present in rice flour.
2. Test tube A serves as a control containing only rice flour and water, which turns blue-black upon adding iodine due to the presence of starch.
3. Test tube B contains rice flour, water, and saliva, where saliva breaks down starch into simple sugars so that iodine does not give a dark blue-black colour.

**Answer:** Yadu wants to test whether saliva breaks down starch into simpler components like sugar.

> Common mistake: Forgetting that iodine turns blue-black in the presence of starch.

### Question 10

*3 marks · Short answer*

Rakshita designed an experiment taking two clean test tubes, A and B and filled them with lime water as shown in the figure. In test tube A, the surrounding air that we inhale was passed on by sucking air from the pipe, and in test tube B, the exhaled air was blown through the pipe (Fig. 9.16). What do you think she is trying to investigate? How can she confirm her findings?

**Solution**

1. Rakshita is trying to investigate whether exhaled air contains more carbon dioxide than inhaled air.
2. Lime water turns milky when it reacts with carbon dioxide.
3. She can confirm her findings by observing that the lime water in test tube B (exhaled air) turns milky much faster or more prominently than the lime water in test tube A (inhaled air).

**Answer:** Rakshita is investigating the amount of carbon dioxide in inhaled versus exhaled air, which can be confirmed by observing the turning of lime water into a milky appearance.

> Common mistake: Confusing which test tube contains inhaled air and which contains exhaled air.

## Frequently asked questions

### How many questions are there in the NCERT Solutions for Class 7 Science Chapter 9 Life Processes in Animals?

The Let Us Enhance Our Learning section has 10 questions in total. These include multiple choice and short answer types based on the new NCERT book for the 2026-27 session.

### Which topics are covered in the exercise questions of this chapter?

The questions cover important concepts such as the action of saliva on starch, breathing rate during physical exercise, and the difference between breathing and respiration. Other topics include the composition of inhaled and exhaled air, the sneezing mechanism, and the human alimentary canal.

### Which question type is considered difficult in this chapter and how should I approach it?

Conceptual questions comparing inhaled and exhaled air or explaining the action of saliva on starch are often found tricky by students. You should approach them by breaking down the scientific terms and writing sequential points to secure full marks.

### How can I write answers to get full marks in Class 7 Science Chapter 9 exams?

To get full marks, use precise scientific keywords related to the human alimentary canal and respiratory system. You can refer to SwaVid's step-by-step solutions on this page to understand the correct structure for each answer.

### Is the free PDF available for Class 7 Science Chapter 9 Life Processes in Animals?

Yes, SwaVid's free PDF and detailed step-by-step solutions are available on this page only. You can use them to prepare for your exams according to the latest NCF 2023 syllabus for the 2026-27 session.

## Related pages

- [Class 7 Science chapters](https://www.swavid.com/science/class/7)

Solutions written by SwaVid, a personal AI tutor for Class 6 to 10 Maths and Science. Practise this chapter free: https://www.swavid.com/start/student