Certified Arborist Practice Exam

Small pores, between guard cells on the undersides of leaves and green plant parts, through which gases are exchanged and water loss is regulated:

1. Stomata

2. Xylem

3. Phloem

4. Compartmentalization Of Decay In Trees

The correct answer is: Stomata

Stomata are small pores located primarily on the undersides of leaves and green plant tissues, crucial for the exchange of gases such as carbon dioxide and oxygen during photosynthesis and respiration. They play a vital role in regulating water loss through transpiration. Guard cells surround each stoma and control its opening and closing, balancing the need for gas exchange while minimizing water loss. The other options pertain to different functions in the plant's physiology: xylem is responsible for the transport of water and nutrients from the roots to the rest of the plant, while phloem transports the products of photosynthesis, like sugars, throughout the plant. Compartmentalization of decay in trees is a process related to how trees manage damage and decay within their tissues, but it does not involve gas exchange or water regulation as stomata do. Thus, stomata are the specific structures responsible for the processes described in the question.