What is photosynthesis primarily used for by plants?

Photosynthesis is primarily used by plants to convert light energy into chemical energy, which is essential for their growth and sustenance. During this process, plants take in carbon dioxide from the atmosphere and water from the soil, using sunlight absorbed by chlorophyll in their leaves. This energy from sunlight is transformed into glucose, a type of sugar that serves as an energy source for the plant. The overall equation for photosynthesis shows this transformation, with light energy facilitating the conversion of inorganic materials into organic molecules.

While the other options present related concepts, they do not accurately describe the primary function of photosynthesis. For example, plants do absorb nutrients from the soil, but this process is distinct from photosynthesis. Likewise, while plants do release some carbon dioxide during respiration, the purpose of photosynthesis is to take in carbon dioxide and convert it into glucose, not to release it. Lastly, cellular respiration is a separate process where plants break down glucose to release energy, which relies on the products of photosynthesis. Therefore, the correct answer reflects the fundamental role of photosynthesis in supporting plant life and energy conversion.