Answer:
A. Air
Explanation:
Abiotic factors are things that are not living.
Air can be found in a rain forest ecosystem, as it can be found in all ecosystems, but it is not living.
On the other hand, algae, flowers, and animals are biotic instead of abiotic because they are living things.
So, A is the correct answer.
I'm pretty sure that it's C. I'm not quite sure though.
Answer:
Explanation
Water in a lake freezes from the bottom up, killing most aquatic organisms. When water in a lake freezes, it floats, providing insulation for organisms below. ... If water were most dense as a solid, lakes would freeze from the bottom up, eventually freezing solid.