Chapter 28, Problem 24A

Summary Introduction

Introduction:

Amphibians include toads, frogs, salamanders, newts, and legless caecilians. Most amphibians are distinguished by moist skin without scales, four legs, exchange of gases through skin, a circulatory system with double loop, lungs, and aquatic larvae.

Answer to Problem 24A

Correct answer:

The correct answer is option (D) lungs.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A) lungs. A tadpole has gills to breath. They do not have lung in the larva stage. During metamorphosis the gills are replaced by lungs. So, the correct answer is option (A).

Explanation for incorrect answer:

Option (B) tail. A tadpole has a long tail to move in water. During metamorphosis the tail shortens and hind legs are formed. So, this is an incorrect option.

Option (C) gills. A tadpole is the limbless, gill-breathing, fish-like larva of a frog. The tadpole undergoes a metamorphosis where hind legs form and grow longer and the tail shorten. So, this is an incorrect answer.

Option (D) herbivorous feeding. A tadpole is a larva of a frog. Tadpoles are specialist herbivores, which feed on planktonic material in the water column, detritus in pond sediment, or scraping material from submerged substrates such as rocks and reeds. So, this is an incorrect answer.