Chapter 29, Problem 6A

Summary Introduction

Introduction:

Reptiles were the first completely terrestrial vertebrates and are fully adapted to live on land. Characteristics like scaly skin, circulatory and respiratory system and shelled egg allow them to succeed on land. They have common characteristics with other organisms such as the presence of an amnion and other membranes.

Answer to Problem 6A

Correct answer:

The correct answer is option (B) As reptiles inhale, the muscles of the rib cage relax.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A) Reptiles are able to suck in air into the lungs by contracting the muscles of the rib cage and the body wall to expand the upper part of the cavity where the lungs are present. Thus, the correct answer is option (B).

Explanation for incorrect answer:

Option (A). Most reptiles use lung for gas exchange. Most of the reptiles, except for some aquatic turtles use lungs for exchange of gas. So, this is an incorrect option.

Option (C) As reptiles exhale, the muscles of the body wall relax. Reptiles are able to suck in air into the lungs by contracting the muscles of the rib cage and the body wall to expand the upper part of the cavity where the lungs are present. They exhale by relaxing the same muscles. So, this is an incorrect answer.

Option (D) The lungs of reptiles have a larger surface area than those of amphibians. The exchange of gas in reptiles takes place in the lungs that have a greater surface area for gas exchange than that of amphibians. With more oxygen, more energy will be released through metabolic reactions that will be made available for complex movements. So, this is an incorrect answer.