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.

(SKIN, CARDIAC MUSCLE) $(i)$ Skin: Frogs respire through their skin (cutaneous respiration) both in water and on land,making it the most important respiratory organ.
(ii) Cardiac muscle: Cardiac muscles are involuntary and exhibit rhythmic,spontaneous contractions throughout life.