The strongest muscles in the human body are found in the:

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 striated muscle contraction:

Which of the following statements is correct regarding skeletal muscles?

Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction.

Identify the muscle which represents the following characteristics and choose the correct option accordingly.
$I.$ Transportation of food through the digestive tract.
$II.$ Transportation of gametes through the genital tract.