Question

In water, frogs respire using ____________.

• A. trachea
• B. skin
• C. buccal cavity
• D. lungs

Hint:

Remember the two key rules for a frog's respiratory shifts:

• In Water / During Hibernation & Aestivation: Respiration is strictly Cutaneous (via the skin).

• On Land: Uses a mix of Pulmonary (lungs), Buccal (mouth lining), and Cutaneous (skin) respiration.

Answer 1

The Correct Option is B

Concept: Amphibians like frogs exhibit diverse respiratory strategies depending on their environment and life cycle stage. Because they divide their life history between aquatic and terrestrial habitats, adult frogs utilize multiple respiratory surfaces: the skin, the lining of the buccal cavity, and the lungs.

Step 1: Analyze respiration in an aquatic medium
When a frog is fully submerged

in water, its primary mode of gas exchange is through its highly vascularized, thin, and moist skin. This process is called

cutaneous respiration. Dissolved oxygen in the water diffuses directly across the thin dermal layer into the subcutaneous blood capillaries, while carbon dioxide diffuses outward into the surrounding water.

Step 2: Understand respiration on land for context
When a frog moves onto land, it can use pulmonary respiration (via the lungs) and buccal respiration (via the moist epithelium lining the oral cavity). However, inside the water, the lungs remain inactive, and gas exchange relies almost entirely on cutaneous diffusion. Therefore, option (2) is correct.