Question

which of these statements is true about autotrophs, but not heterotrophs?
they use sugar and oxygen to make carbon dioxide and water.
they use chlorophyll and oxygen to make carbon dioxide and water.
they use sunlight, water, and carbon dioxide to make sugars.
they use sunlight, water, and oxygen to make chlorophyll.

Explanation:

Autotrophs perform photosynthesis. The process of photosynthesis uses sunlight, water ($H_2O$), and carbon dioxide ($CO_2$) to produce sugars (such as glucose, $C_6H_{12}O_6$) and oxygen ($O_2$). Heterotrophs cannot perform this process. Option A describes cellular respiration (used by both autotrophs and heterotrophs). Option B has incorrect reactants and products for photosynthesis. Option D is not a correct description of a biological process related to autotrophs.

Answer:

C. They use sunlight, water, and carbon dioxide to make sugars.