Leaves of green plants contain openings known as stomata. These are opened and closed by specialized cells that allow gases to be exchanged between the leaf and the outside environment. Which of the following best describes the flow of gases into and out of a leaf through stomata on a sunny day?
a
Carbon dioxide and oxygen move in; ozone moves out.
b
Oxygen moves in; nitrogen moves out.
c
Water vapor and ozone move in; carbon dioxide moves out.
d
Carbon dioxide moves in; oxygen moves out.
d. Carbon dioxide moves in; oxygen moves out.
To determine the correct answer, let's think about the process of photosynthesis and respiration, which are the main processes occurring in leaves.
During photosynthesis, green plants use sunlight, carbon dioxide, and water to produce glucose (sugar) and oxygen. This process happens in the presence of chlorophyll, which gives leaves their green color.
On the other hand, during respiration, plants consume oxygen and produce carbon dioxide as a byproduct.
Considering these processes, we can conclude that on a sunny day, the flow of gases into and out of a leaf should be as follows:
Carbon dioxide moves in, and oxygen moves out.
Therefore, option d, "Carbon dioxide moves in; oxygen moves out," is the most accurate description of the gas flow through stomata on a sunny day during photosynthesis and respiration.