Question

A) Give scientific reasons.(Any One)
1) While doing exercise we feel tired.
2)At the time of evolution of human being their hands were free doing work.
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Answer 1

Answer:

2)At the time of evolution of human being their hands were free doing work.

Answer 2

1) Reason:

• As we know that anaerobic respiration is performed by muscle cells while doing exercise.

• The lactic acid accumulates in the body during anaerobic respiration. lactic acid accumulates due to the breakdown of glucose.

• During anaerobic respiration, ATP is produced in less amount so that we feel tired while doing exercise.

2) Reason:

• At the time of the evolution of human beings, their hands were free to do work.

• As we know that the evolution of human hands assumes a short thumb with a long hand.

• They used their hands for making stone tools.