Answer:
gas source
Explanation:
Photosynthesis is not an example of the greenhouse effect. The greenhouse effect represents the excess of gases released by fossil fuels, such as CO2. Photosynthesis filters this gas from the atmosphere and does not contribute to its accumulation.
Photosynthesis is not an example of anthropogenic effect either. Anthropogenic effect is a term that corresponds to the change in the concentration of ozone in the atmosphere by manufactured compounds, resulting from human activities and which, through chemical reactions cause their destruction. Photosynthesis is not a man-made process and it also does not damage the atmosphere.
Secondary pollutants are those formed in the atmosphere through chemical reactions between the primary pollutants. With this concept, we cannot consider that photosynthesis is an example of secondary pollutants, since photosynthesis does not promote any kind of pollution in the atmosphere.
For this reason, we can consider that photosynthesis is an example of a gas source, since it is through photosynthesis that plants can capture carbon dioxide from the atmosphere and release oxygen (which is also a gas) into the atmosphere.