Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What are the primary structures in plants involved in gas exchange?

1. Stomata

2. Roots

3. Flowers

4. Phloem

The correct answer is: Stomata

Stomata are the primary structures in plants responsible for gas exchange. They are small openings found primarily on the surfaces of leaves and stems, which allow for the exchange of gases—specifically, the uptake of carbon dioxide and the release of oxygen during photosynthesis, as well as the release of water vapor in a process known as transpiration. The presence of stomata facilitates these critical processes that support the plant's growth and development while also playing a significant role in regulating water loss. Roots, while essential for nutrient and water absorption from the soil, do not play a direct role in gas exchange with the atmosphere. Flowers are primarily involved in reproduction, attracting pollinators, and facilitating fertilization, but they do not directly contribute to the gas exchange process needed for plant metabolism. Phloem is the vascular tissue responsible for transporting nutrients, particularly sugars, throughout the plant, but it is not involved in gas exchange. Thus, stomata are the key structures that enable plants to interact with their environment in terms of gas exchange.