Answer: A) changing the rate at which greenhouse gases are released from Earth's surface into the environment.
Explanation: Without vegetation (For example trees) the rate at which greenhouse gases, like carbon dioxide, are released from Earth's surface into the environment would skyrocket. Vegetation uses carbon dioxide in photosynthesis and converts it into oxygen, helping to absorb some of the greenhouse gases that would otherwise accumulate in our atmosphere. It essentially reduces the rate at which greenhouse gases are released into our atmosphere.