Class 7 Science Chapter 9 Life Processes in Animals Question Answer | NCERT Solutions

 

Science Class 7 Chapter 9 Question Answer Life Processes in Animals

Life Processes in Animals Class 7 Question Answer (InText)

Question 1.

Cows keep chewing the food even when they are not actively grazing or eating anything. Why? (Page 127)

Answer:

Cows continue to chew even when they are not eating, as they are ruminating (chewing cud) to aid in the digestion of their food

more effectively. This allows them to get the nutrients they need from rigid plant material.

Question 2.

Is the process of respiration the same in all animals? (Page 128)

Answer:

No, respiration is not the same in all animals. It depends on their size, habitat, and complexity.

NCERT Class 7 Science Chapter 9 Question Answer Life Processes in Animals (Exercise)

Question 1.

Complete the journy of food through the alimentary canal by filling up the boxes with appropriate parts

Answer:

Question 2.

Sahil placed some pices 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.

Answer:

The observations can be explained by the given table:

Material	Iodine solution	Observation	Reason
Sahil – Chapati	Yes	Blue-black colour	Starch is present and undigested
Neha – Chewed chapati	Yes	Slight or no colour change	Starch is partially digested into sugars by salivary amylase
Santushti – boiled and mashed potato	Yes	Blue-black colour	Potato contains a lot of starch that reacts strongly with iodine

Question 3.

What is the role of diaphragm in breathing?

(i) To filter the air

(ii) To produce sound

(iii) To hep in inhalation and exhalation

(iv) To absorb oxygen

Answer:

(iii) To help in inhalation and exhalation

Question 4.

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

Answer:

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

Question 5.

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

Answer:

Sanvi can ask the following questions to Anil to make him understand that breathing and respiration are not the same process:

1. Do plants breathe? How do they get oxygen?
2. Does the carbon dioxide we exhale come from respiration or breathing?
3. Can we perform respiration without breathing for a short time?
4. Can you give an example of a process that involves breathing but not respiration?

Question 6.

Which of the following statement is correct and why?

Anu: We inhale air.

Shanu: We inhale oxygen.

Tanu: We inhale air rich in oxygen.

Answer:

Tanu’s statement is correct: We inhale air rich in oxygen. When we inhale, we take in air that contains about 21% oxygen and exhale air having more carbon dioxide than inhaled air.

Question 7.

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

Answre:

When we inhale a lot of dust-laden air, the dust particles get trapped in the hair of our nasal cavity. These particles irritate the lining of the cavity. As a result, we sneeze to expel these dust particles. Sneezing expels these foreign particles from the inhaled air, and dust-free, clean air enters our bodies.

Question 8.

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 breating faster than Paridhi. Provide at least two possible explanations for why Anusha was breathing faster than Paridhi.

Answer:

Two possible explanations:

• Anusha might not be fit and healthy, and her lungs were not working efficiently.
• She might have asthma or a cold, and she was struggling to get enough oxygen.

Question 9.

Yadu conducted an experiment to test his idea. He took two test tubes, A and B, and added a pinch of rich 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?

Fig. Experimental results

Answer:

Yadu wants to test the presence of starch in both test tubes.

Question 10.

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?

Fig. Experimental set-up

Answer:

Rakshita is trying to inve stigate the gas we inhale and exhale while breathing. The lime water in test tube B turned milky (or cloudy), but the lime water in test tube A did not. Lime water turns milky when it reacts with carbon dioxide. Therefore, this indicates that the exhaled air contains more carbon dioxide than the air we inhaled.

Class 7 Life Processes in Animals Question Answer (Activities)

Activity 9.1: Let Us Investigate (Page 123)

Table 9.1: Action of saliva on starch

Test tube	Initial colour before adding iodine	Final colour after adding iodine	Possible reason for the change in colour
A: Boiled rice	White	Blue-black	Boiled rice contains starch, which reacts with iodine to give a blue-black colour.
B: Chewed boiled rice	White or slightly off-white	No change/ Faint blue black	Saliva contains a digestive juice that breaks down starch into sugars, reducing the starch content. Hence, little or no blue-black colour appears.

Activity 9.2: Let Us Make a Model (Page 130)

Fig. (a) Inhalation (b) Exhalation

Observation and conclusion:

• This experiment mimics the inhalation and exhalation processes of breathing. When the rubber sheet at the base of the bottle is pulled downward, the space inside the bottle increases. As a result, air is drawn into the balloon, and it inflates, just like the lungs do during inhalation. This shows how the diaphragm moves down and creates an area in the chest, allowing air to flow into the lungs.

• When the rubber sheet is pushed back upward, the space inside the bottle decreases and pressure increases, forcing air out of the balloon. This shows exhalation, where the diaphragm relaxes and moves up, reducing space and pushing air out of the lungs.

Activity 9.3: Let Us Explore (Page 131)

Fig. (a) Air is passed into lime water with a pichkari/syringe

(b) Air is exhaled into lime water

Observation: The lime water in test tube B turns milky as it receives exhaled air but the lime water in test tube A does not.

Conclusion: This indicates that exhaled air contains carbon dioxide. Lime water reacts with carbon dioxide to form calcium carbonate, which causes the milky appearance. The change only in test tube B confirms that more carbon dioxide is present in the air we breathe out than in the air we breathe in.