Chapter 22, Problem 21A

Summary Introduction

Introduction:

The leaves of plants are involved in photosynthesis and the structures of the leaves are such that it is well adapted to this function. Stomata are specializedstructures found in leaves that are involved in respiration and transpiration. It is a small opening through which the water, carbon dioxide, oxygen, and other gases pass.

Answer to Problem 21A

Correct answer:

The correct answer is option (C)guard cell.

Explanation of Solution

Explanation/justification for the correct answer:

Option (C) guard cell.The stomata have an opening which is covered by guard cells. The guard cells are specialized present in the epidermis of leaves and the opening and closing of the guard cells control the gas exchange through stomata.So, the correct answer is option (C).

Explanation for incorrect answer:

Option (A) bark. The bark is the outer layer of the tree. They are made of dermal cells.It is involved in protecting the plant from the external environment. So, this is an incorrect option.

Option (B)pericycle. The pericycle is found next to the epidermis towards the center of the root. This tissue is involved in the formation of lateral roots. So, this is an incorrect option.

Option (D) vascular tissue. In leaves,the vascular tissue is found in the petiole. This is a vascular tissue that connects the vascular tissue of stem and leaf. So, this is an incorrect answer.