Myofilaments myofilaments include actin and myosin are responsible for shortening muscle cells are specific types of microfilaments all of the answers listed are correct.

Answer : All the listed options are correct .

Myofilaments are present in myofibrils, a special component of muscle cell or muscle fibre. They are made of proteins. They are hair like structure so also called as microfilaments .There are two type of myofilaments present :

A) Thick filament : This filament is made of protein known as " Myosin " . Myosin provides elasticity and contractibility to muscles.

B) Thin filament : This filament is made of protein known as " Actin " , which helps in contraction mechanism .

Following are attached diagram for Myofilaments .

where is the diagram?

if you insert the diagram ill be able to you

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.