Chapter 16, Problem 6A

Summary Introduction

Introduction :

Humans, apes, monkeys and lemurs are a group of mammals called primates. They are highly diverse mammals but share some general features. Some primates have a high level of manual dexterity which is the ability to manipulate or grasp objects with their hands. They usually also have keen eyesight and long, highly movable arms. Compared to other animals, they have large brains.

Answer to Problem 6A

Correct answer:

The correct answer is option (C) opposable digits.

Explanation of Solution

Explanation/justification for the correct answer :

Option (C) opposable digits. An opposable first digit, either a thumb or a great toe is set apart from the other digits. This digit can be brought across the palm or foot so that it touches or nearly touches the other digits. This action allows the primate to grasp an object in a powerful grip. Thus, this is the correct answer.

The explanation for the incorrect answer :

Option (A) complex brain. Brain is the center of thought. It is not adapted for better griping. Thus, this is an incorrect option.

Option (B) flexible forelimbs. The flexible forelimbs help the mammals to move easily on the ground or in the trees. Thus, this is an incorrect answer.

Option (D) prehensile tail. A prehensile tail in New World monkeys functions like a fifth limb. It can grasp tree branches or other objects and support a monkey’s weight. Thus, this is an incorrect answer.