What are the two main stages of photosynthesis?

The two main stages of photosynthesis are indeed the light-dependent reactions and the Calvin cycle.

In the light-dependent reactions, which occur in the thylakoid membranes of the chloroplasts, sunlight is captured by chlorophyll and other pigments. This energy is used to convert water into oxygen, protons, and electrons, and it also generates ATP and NADPH, which are essential energy carriers. This stage of photosynthesis is dependent on light, hence the name.

The Calvin cycle, also known as the light-independent reactions, takes place in the stroma of the chloroplasts. During this stage, the ATP and NADPH produced in the light-dependent reactions are utilized to convert carbon dioxide from the atmosphere into glucose. This process does not require light directly, but it relies on the energy carriers produced in the light-dependent stage.

Other options provided do not accurately represent the stages of photosynthesis. While respiration is a related metabolic process, it is not considered a stage of photosynthesis. Similarly, "dark reactions" is an outdated term that often refers to what we now understand as the Calvin cycle. The electron transport chain and oxygen generation are components of the light-dependent reactions but do not encompass the full process of photosynthesis.