A codon is a sequence of DNA that codes for something
C photic zone because that is where sunlight can reach and you need sun for photosynthesis
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.
If my memory serves me well, the most suitable from given above is:
a) testes → epididymis → vas deferens → urethra