Chapter 30, Problem 21A

Summary Introduction

Introduction:

The monotremes are the animals that lay eggs instead on giving birth to the young ones. The duck billed platypus is a monotreme who’s moth resembles to the bill of a duck.

Answer to Problem 21A

Correct answer:

Option (C).

Explanation of Solution

Explanation/justification for the correct answer:

Option (C) three chambered heart. All the birds and the mammals, including the monotremes have a four chambered heart. Hence, the correct answer is option (C).

Explanation for incorrect answer:

Option (A) webbed feet. Platypus are semi aquatic; they have a webbed feet that helps in swimming.

Option (B) egg laying ability. The platypus are monotremes, which lay eggs. Hence, it is an incorrect answer.

Option (D) small reptile like chromosomes. The chromosomes of the platypus are generally small and resembles to the reptiles. Hence, it is an incorrect answer.