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
Oxygen moves in; nitrogen moves out.
b
Carbon dioxide moves in; oxygen moves out.
c
Carbon dioxide and oxygen move in; ozone moves out.
d
Water vapor and ozone move in; carbon dioxide moves out.
b
Carbon dioxide moves in; oxygen moves out.
b) Carbon dioxide moves in; oxygen moves out.
To determine the correct answer, we need to understand how gases move in and out of the leaf through stomata on a sunny day.
During photosynthesis, green plants use sunlight to convert carbon dioxide and water into glucose, releasing oxygen as a byproduct. Therefore, the correct answer must involve the movement of carbon dioxide and oxygen.
Option a: Oxygen moves in; nitrogen moves out. This option is incorrect as nitrogen is not directly involved in the process of gas exchange during photosynthesis.
Option b: Carbon dioxide moves in; oxygen moves out. This option is correct. On a sunny day, as the plant performs photosynthesis, it takes in carbon dioxide from the atmosphere through its stomata and releases oxygen back into the surroundings.
Option c: Carbon dioxide and oxygen move in; ozone moves out. This option is incorrect as ozone is not directly involved in gas exchange in the process of photosynthesis.
Option d: Water vapor and ozone move in; carbon dioxide moves out. This option is incorrect as water vapor is primarily involved in transpiration (the evaporation of water from the leaves) and ozone is not directly involved in gas exchange during photosynthesis.
Therefore, the correct answer is: b) Carbon dioxide moves in; oxygen moves out.