The Calvin cycle occurs in:

Explanation

In the stroma of the chloroplast, carbon dioxide is fixed into organic molecules using ATP and NADPH produced during the light reactions. Prokaryotes do not have chloroplasts, although some photosynthetic bacteria carry out similar processes in their cytoplasm. Mitochondria are the sites of cellular respiration, not photosynthesis, and are involved in energy release rather than carbon fixation. The cytoplasm is where other metabolic processes like glycolysis occur, but it does not carry out the Calvin cycle. Glyoxysomes are specialised organelles involved in fat metabolism in germinating seeds, not in photosynthesis. Therefore, the Calvin cycle occurs only in the chloroplasts.