Chapter 34, Problem 8STP

Summary Introduction

Introduction :

Mammals are animals with hair and mammary glands. Young mammals are fed milk from their mother's special mammary glands. In addition to these characteristic milk glands, mammals are characterized by several other distinctive features. Hair is a typical mammalian trait, although it has disappeared in many whales. The lower mammalian jaw is clamped directly to the skull instead of through a separate bone (quadrate) as in all other vertebrates.

Answer to Problem 8STP

Correct answer :

The correct answer is option (A) four-chambered heart.

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) four-chambered heart. Mammals have a four-chambered heart. The oxygenated blood is kept entirely separate from deoxygenated blood in mammals. Because most of the mammals are physically active and all require a consistent supply of nutrients and oxygen to maintain homeostasis. So, this is the correct option.

Explanation for incorrect answer :

Option (B) high metabolic rate. The food of mammals provides them high energy levels. High levels of oxygen also are required to maintain a high level of metabolism. The high level of metabolism does not relate to homeostasis. So, this is an incorrect option.

Option (C) milk production. Milk production does not affect homeostatic temperature control in mammals. So, this is an incorrect answer.

Option (D) signaling devices in fur. Hair also can function as a signaling device. It is not related to homeostasis. So, this is an incorrect answer.