Oxygen can be stored in

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 $:-$

In which of the following muscle components are actin-binding sites present?

Unstriped muscles are found in

The sheath covering the bundle of muscle fibres is

Shivering with cold in winter is caused by