The portion of the muscle fibre between two successive ___________ (A) is considered as the functional unit of contraction and is called a ____________ (E) . In a resting state, the edges of thin filaments on either side of the thick filaments partially overlap the free ends of the thick filaments leaving the central part of the thick filaments. This central part of thick filament, not overlapped by thin filaments is called the __________ (D) .

Question

( a ) ‘Z’ lines , sarcomere; ‘A’ band
( b ) ‘Z’ lines , myofibril; ‘A’ band
( c ) ‘Z’ lines , sarcomere; ‘H’ zone
( d ) ‘I’ bands , myofibril; ‘A’ band