Some algae have chloroplasts and chlorophyll and obtain their energy through photosynthesis while some algae like euglena are both heterotrophic (decompose dead organic matter) and autotrophic (use photosynthesis) and can also obtain energy likewise.
It is caused by the atmosphere of the Earth. It is due of the scattering of light by the atmosphere. When the moon is near the horizon, the moonlight must pass through much more atmosphere than when the moon is directly overhead.
Protein can be reversed to make glucose so the answer is protein