Answer:
If you're on EDGE 2021, it's NOT D.
I think it's A.
Yes it is , <span>A hypothesis is a reasonable guess based on what you know or observe.</span>
Explanation:
What happens during daytime is, oxygen that gets trapped between filaments of algae, moves them to the surface and during night as O2 is not produced, they slowly sink to lower depths, and you don't see them
All arthropods Have Exoskeletons . Hope I helped
