A benefit of using nuclear energy could be the abundance of uranium in nature. The human risk about mining that is the most important to consider are the health hazards that are associated with uranium mining.
Photosynthesis is when plants use sunlight to synthesize food from carbon dioxide. Plants are autotrophs (they make their own food) and the food they synthesize creates carbohydrates, so the correct answer is D - autotrophs produce carbohydrates.
Hope this helps.
