How do plants contribute to air quality?

Plants play a crucial role in improving air quality primarily through the process of photosynthesis. During photosynthesis, plants absorb carbon dioxide from the atmosphere and, using sunlight as energy, convert it into glucose and oxygen. The oxygen produced is released into the air as a byproduct, which is essential for the survival of most living organisms, including humans. This process not only helps to reduce the levels of carbon dioxide, a greenhouse gas, but also contributes to the oxygen supply in the atmosphere, enhancing air quality.

While other options touch on important aspects of plant function, they do not directly address the primary way in which plants contribute to cleaner air. For instance, providing carbohydrates or food sources is an important ecological service of plants but does not relate to air quality. Similarly, while having chlorophyll is essential for photosynthesis, it is the oxygen production that specifically leads to improved air quality.