The major protein in the thick filament of skeletal muscle fibre is

$A$ bundle of muscle fibre is called

Body contraction is due to the pulling of ....

Skeletal muscles are closely associated with the $...A...$ components of the body. They have $... B...$ appearance under the microscope and hence are called $...C...$ muscles.
Choose the correct options to fill $A, B$ and $C$,so as to complete the given $NCERT$ statement.

The muscles immune to fatigue are

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.