Which Statement Represents the Best Rephrasing of the Following Statement

Multiple Choice

Which statement represents the best rephrasing of the following statement: "Guard cells control gas exchange"?

A) Guard cells in the epidermis open and close the pores used for gas exchange.
B) Gases move through guard cells.
C) Guard cells are involved in photosynthesis.
D) Guard cells pump gases into and out of the leaf.
E) Carbon dioxide enters the leaf through epidermal cells.