Lack of relaxation between successive stimuli in sustained muscle contraction is known as

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.

In muscular hypertrophy,what happens to the muscle cells?

In the resting state,a subunit of troponin masks the active binding sites for .......... on the .......... filaments.

What are $HMM$ and $LMM$?

The dark bands in a myofibril are due to the presence of: