Contraction of a muscle is caused by

During muscle contraction,which of the following events occurs?

Both proteins,actin and myosin,are arranged in a rod-like structure in the muscles:

Given below are two statements $:-$
Statement-$I$ :- Each organised skeletal muscle in human body is made of a number of fascicles,held together by a common connective tissue layer called fascia.
Statement-$II$ :- The portion of the myofibril between two successive '$Z$' lines is considered as the functional unit of muscle contraction,known as a sarcomere.
In the light of the above statements,choose the correct answer from the options given below $:-$

What do ligaments connect?

During muscle contraction in humans,the