Where are calcium ions stored in muscle cells?

Latissimus dorsi muscles are:

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 region at the ends of the $A$-band of two adjoining sarcomeres is called

Bone-dissolving cells are known as..........

In the mechanism of muscle contraction or shortening of muscle,the . . . . . . get reduced whereas the . . . . . . retain the length.