In the diagram depicting force velocity relationship of skeletal muscle, the difference between the three curves is mainly due to?

Ans. (d) Myosin ATPase activity(Ref: Guyton 13th ed p.81)Simply remember, velocity of contraction is maximum when there is no load (weight) to be lifted at all and it decreases whenever the load (weight) increasesThe maximum velocity of shortening depends on myosin ATPase activity of the muscle which is the sole reason behind the difference in these three curves