Photosynthetic organisms produce oxygen based on whether light is available for photosynthesis. These organisms also consume oxygen for cellular respiration in both light and dark environments. In three to five sentences, explain how these conditions relate to gross and net productivity. (4 points)

Gross productivity refers to the amount of carbon fixed.

Explanation:

Gross productivity refers to the amount of carbon fixed during the process of  photosynthesis by all producers such as plants and algae etc in the ecosystem. A large part of the energy that is produced in the process of photosynthesis is used by the plants in the metabolic processes of the producers such as respiration. The net productivity indicates that carbon dioxide plants that is used during the photosynthesis process substracted from carbon dioxide the plants releases during the process of respiration.

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.