In the Northern Hemisphere, climate scientists observe seasonal changes in carbon dioxide concentration with the highest levels measured in May and the lowest levels measured in October. Hypothesize how photosynthesis can affect these changes. Explain your answer in three to five sentences.

In the Northern Hemisphere, the seasonal variation in carbon dioxide (CO2) levels is closely tied to photosynthesis. During the spring and summer months, when temperatures rise and daylight hours increase, plants are more actively engaged in photosynthesis, which absorbs CO2 from the atmosphere. This process leads to a decrease in atmospheric CO2 levels, reaching their lowest point around October when plant growth slows down and leaves fall, reducing photosynthetic activity. By May, as plants flourish and grow, their uptake of CO2 peaks, contributing to the observed high concentrations in the atmosphere, correlating with the seasonal cycle of plant growth and decay.