The immediate energy source for muscle contraction is:

Which of the following are the special properties of muscles?

Describe the mechanism of muscle contraction with a diagram.

Select the correct option for skeletal muscle.
$(I)$ In human body,it is made of a number of muscle bundles.
$(II)$ Muscle bundles contain a number of muscle fibers and each fiber is lined by the sarcolemma.
$(III)$ In a muscle fiber,the sarcoplasm contains only one nucleus.
$(IV)$ In a muscle fiber,the sarcoplasmic reticulum is the storehouse of calcium ions.

Contraction of the muscles takes place by the sliding of

The given figure represents the cross-bridge cycle in skeletal muscle. What does step $B$ in the figure represent?