$A$ ...... muscle rotates the forearm to turn the palm downwards.

Globular head with a short arm and a tail are the two important parts of

The sliding filament theory can be best explained as:

Select the correct statement with reference to muscle structure.
$I.$ Each myosin is a polymerized protein.
$II.$ Many meromyosin constitute one thick filament (myosin).
$III.$ Each meromyosin's tail is called heavy meromyosin $(HMM)$ and head is called light meromyosin $(LMM)$.
$IV.$ The globular head is an active $ATPase$ enzyme and has binding sites for $ATP$ and active sites for actin.
Choose the option with correct statements.

Identify the incorrect statement regarding muscle contraction.

Which ion binds with troponin during muscle contraction?