Chapter 3, Problem 1A

Summary Introduction

Introduction:

The “surface area-to-volume” ratio helps in explaining the relation between a cell’s surface area and its size.

Answer to Problem 1A

Correct answer:

As the cell size decreases, the ratio its surface area to volume increases. Therefore, option (a) is correct.

Explanation of Solution

Reasons for the correct statement:

The surface area to volume ratio increases, when there is decrease in the size of the cell. Accordingly, as the cells have smaller size, they tend to possess a surface area that is large, and so, as the size of the cell decreases, the ratio increases.

Option (a) is given as “increases”.

“As the size of a cell decreases, the ratio of its surface area to volume increases”, it is the right answer”.

Hence, option (a) is correct.

Reasons for the incorrect statements:

Option (b) is given as “decreases”.
As the size of a cell will increase, then the ratio of surface area to volume would decrease, not when the cell size will decrease. So, it is a wrong answer.

Option (c) is given as “stays the same”.
As the cell size decreases, the ratio its surface area to volume increases, however it does not remain the same. So, it is a wrong answer.

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

Conclusion

:

As the cell size decreases, then the ratio to its surface area to volume increases.