The dark bands ($A$-bands) of a skeletal muscle are known as

Which of the following statements is correct regarding muscle contraction?

The region between two successive $Z-$lines in a myofibril is

Describe the important steps in muscle contraction.

Select the correct option for the following statements:
$(i)$ The most important respiratory organ in frogs is the skin / lungs.
(ii) Skeletal muscle / Cardiac muscle exhibits rhythmic contraction.

In a skeletal muscle fiber,how many actin filaments surround each myosin filament?