'Gastrocnemius' is a muscle of

In striated muscle contraction:

The structural and functional unit of myofibril which contracts to cause movement is called

Analogy type questions:
$(1)$ Red muscle fibers / White muscle fibers have fewer mitochondria but more sarcoplasmic reticulum.
$(2)$ When nerve impulses reach the neuromuscular junction,acetic acid / acetylcholine neurotransmitter is released.

Flexion of the thigh,knee,and their rotation is facilitated by:

$A$ motor unit is a