NCERT Solutions for Class 7 science Chapter 9: Life Processes in Animals Class 7

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.

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.

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

Answer:

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:

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

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:

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.

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.

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:

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.

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.