Chapter 31, Problem 1MCQ

Summary Introduction

Introduction:

Breathing is a mechanical process where the gases are exchanged between the lungs and the atmosphere. Breathing is the first step of respiration. Breathing occurs due to the changes in the pressure in the thorax or chest cavity of the body.

Answer to Problem 1MCQ

Correct answer:

The main purpose of breathing in human beings is to exchange gases and to support the cellular aerobic respiration taking place in mitochondria.

Therefore, option (d) is correct.

Explanation of Solution

Reason for correct statement:

Breathing is the process of exchange of gases that is inhalation of oxygen gas and exhalation of carbon dioxide. The oxygen gas taken in by the breathing process is used in the aerobic respiration that takes place in mitochondria of the cell.

Option (d) is given as “Both a and b are correct”.

As, “breathing helps in the elimination of ${\text{CO}}_{\text{2}}$, and also supports the cellular aerobic respiration occurring in the mitochondria” is the right answer.

Hence, option (d) is correct.

Reasons for the incorrect statements:

Option (a), is given as “To eliminate ${\text{CO}}_{\text{2}}$”.

The breathing process helps in the exhalation of the carbon dioxide gas from the body. As other statements given are also correct, Hence, it is a wrong answer.

Option (b), is given as “To support aerobic respiration in mitochondria”.

Breathing process helps in the intake of oxygen in the body that helped in the aerobic respiration occurring in the mitochondria. As other statements given are also correct, Hence, it is a wrong answer.

Option (c), is given as “To keep the respiratory surface dry”.

Breathing process does not play any role in the drying of the respiratory surface. Hence, it is a wrong answer.

Hence, options (a), (b), and (c), are incorrect.

Conclusion

Breath in means the inhaling of the oxygen gas while breath out means the exhaling of the carbon dioxide gas.