Question

Respiration in the adult frog is
A. Cutaneous
B. Buccal
C. Pulmonary
D. All the above

Answer 1

Frogs can live both on land and in fresh water and belong to the Phylum Chordata Amphibia class. By using two different approaches with the aid of different organs intended for that, they respire on land and in the sea. Gills are absent in adult frogs, but they also have a diffusion strategy in water and soil.

Complete answer:
The oral cavity, skin, and lungs are the respiratory organs of an adult frog on the ground. In water, the skin of adult frogs is used as a respiratory organ called skin respiration. Pulmonary respiration is called breathing through the lungs.
A frog may also breathe a lot like a human while living on the ground, taking air through their nostrils and into their lungs, but the mechanism is slightly different.
Buccal respiration is 'respiring through ': a breathing system used in which while respiring the animal moves the floor of its mouth in a rhythmic manner that is externally visible. In amphibians, it is the only way the lungs can be inflated.
The frog lowers the floor of its mouth in order to draw air into its mouth, which causes the throat to expand. The nostrils are then opened to allow air to enter the mouth. The nostrils then close and the air within the mouth is forced into the lungs by contraction of the mouth floor. The mouth floor moves down to remove the $CO2$ within the lungs, drawing the air out of the lungs and into the mouth. Finally, the nostrils are opened and the floor of the mouth rises to push the air out of the nostrils. The skin is made up of thin membranous tissue, which is very water-permeable and has a large network of blood vessels. The thin membranous skin makes it possible for the respiratory gas to spread its gradients rapidly directly between the blood vessels and thus the atmosphere.
Thus, the correct response is B- buccal.

Note: When the frog is out of the water, the mucous glands in the skin keep the frog moist, helping to remove dissolved oxygen from the air. Frogs often have a breathing surface on which the gas is easily exchanged. This function is their main mode of breathing while sleeping, seldom filling the lungs. This is because the lungs found only in adult frogs are poorly developed.