Answer:
Stroma
Explanation:
Chloroplasts are the double membrane-bound organelles. They have a third internal membrane system called thylakoids. Thylakoids are disc-shaped and are stack upon each other. Stacked thylakoids are called grana. The fluid-filled space present outside the thylakoid membranes of the chloroplast is called stroma. Stroma is rich in many bio-molecules. The enzymes for the Calvin cycle are present in the stroma. Therefore, stroma serves as the site for the Calvin cycle which in turn fixes the atmospheric CO2 into glucose.
