The sun provides the energy for photosynthesis. Cells use sugar as a source of energy. The products of cellular respiration are CO2 and H2O. These products are used by plants to make sugar and oxygen through photosynthesis.
The homo erectus is the most common ancestor with modern humans
Only once because the DNA replication initiation is tightly linked to cell cycle progression,ensuring that replication occur only once per cycle
Answer:
Biotic factors are just everything living (bio-) in an ecosystem. So they're bound to vary in every ecosystem, based on the biome, climate, other food sources available, et cetera.
Do you see flamingoes in the forest? No, you say? Well, they're living; they're biotic factors. They aren't in a forest or a jungle ecosystem because that's not their habitat and they don't thrive there.