Neuromuscular junction is a junction between

How many main types of muscles are there?

In a $A$ state,the edge of thin filaments on either side of thick filaments $B$ overlap the free ends of $C$ filaments leaving the central part of thick filaments. This central part of thick filament,not overlapped by thin filaments is called $D$ zone.
Choose the correct options to fill the gaps $A, B, C$ and $D$,so as to complete the given $NCERT$ statement.

Sliding filament theory can be best explained as

During muscle contraction,$ATP$ provides energy for

$A$ collagenous connective tissue layer holds the muscle bundles together.