Assertion: A person undergoes fatigue very soon during exercies.
Reason : Muscle fibres undergo oxygen debt during exercies.

Options

A. If both assertion and reason are ture and reason is the corect explanation of assertion
B. If both assertion and reason are ture but reson is not the correct explanation of assertion
C. If assertion is true reason is false
D. If both assertion and reason are false

Answer

b

Explanation

During strenous exercise, the muscle does not get sufficient oxygen to meet its energy requirement immediately. So, muscle contracts in the absence of oxygen. But it gets fatigued sooner in the absence of oxygen as the metabolic products of cellular respiration mainly lactic acid accumulates. The accumulation of lactic acid leads to muscle fatigue.
After strenuous exercise, the oxygen consumption of muscle exceeds. The extra oxygen consumed during recovery is called debt of muscle. It is used in oxidizing the accumulated lactic acid aerobically and in restoring the depleted creatine phosphate and ATP in the muscle fibre. A small part of oxygen debt also goes to myoglobin which binds and stores oxygen for future use.