Answer:
a. Voluntary.
Voluntary means the work which can be done according to the individual's will. Skeletal muscles are under voluntary control that maintains the movement of hand, legs and muscles movement.
b. Striated.
Striated means the presence of dark and light bands of skeletal muscles when placed under the microscope. Cardiac muscles also shows striation.
c. Reason of striation.
The presence of actin and myosin protein present in the muscle is responsible for the striations of the skeletal muscle. The thick filament is formed by myosin and thin filament is formed by actin protein.