The primary source of water gain for most amphibian species is __?
A Cutaneous drinking
B Oral drinking
C Preformed water
D Metabolic water
The correct answer and explanation is:
The correct answer is A. Cutaneous drinking.
Amphibians are known for their unique ability to absorb water through their skin, which is their primary source of water intake. This process is called cutaneous drinking. Unlike many other animals that drink water orally, amphibians have specialized skin that allows for the absorption of moisture directly from their environment, particularly from moist surfaces like the ground or plants. This is especially critical for amphibians that live in environments with fluctuating water availability, as they may not always have access to standing water or may not need to drink in the traditional sense.
The skin of amphibians is permeable to water, and they can absorb it to maintain hydration. This is important because amphibians often have limited access to fresh water sources, and their skin is an efficient alternative way to fulfill their water requirements. For instance, in terrestrial amphibians, the skin may be used to absorb water during rainy conditions or when they are near moist areas.
In addition to cutaneous drinking, amphibians can also gain some water from other sources, such as oral drinking (B) and preformed water (C), which comes from food and metabolic processes. Metabolic water (D), produced during cellular respiration, is typically a secondary source of water and does not play as significant a role in amphibians’ water gain compared to cutaneous drinking.
This ability to absorb water through the skin allows amphibians to survive in environments where water is scarce or when they are not actively near water bodies. This adaptation is especially important in species like frogs, salamanders, and newts, which might spend a significant portion of their lives on land.