Assertion Muscle as a whole does not obey All-or-none law.
Reason Each muscle fibre contracts maximally whenever it contracts.

Options

A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
B. Both Assertion and Reason are true, but Reason is not the correc explanation of Assertion
C. Assertion is false, but Reason is true
D. Both Assertion and Reason are false

Answer

b

Explanation

Muscle as a whole does not obey All or None law, although individual muscle fibre consitituting the muscle obey it. This is due to the fact that the strength of the threshold stimulus varies can stimulus varies from muscle fibre to muscle fibre. A weak stimulus can stimulate only a few fibres, which have low threshold, but a stronger stimulus stimulates a larger number of fibres by stimulating even those with high thresholds.