Pollution :) Since Abiotic means non living.
Bacteria: Living
Food (worms or smaller fish): Living
Predators: Living
Pollution (dirt, trash, or other stuff): Non Living
They are said to be “denser” than air. what happens is that light slows down when it passes from the less dense air into the denser glass of water. this slowing down the ray of light also causes the ray of light to change directions. it is the change in the speed of the light that causes refraction.
The horse will give 32 chromosomes and donkey will give 31 chromosomes to the offspring.
The offspring has 63 in total.
It is odd so it can not produce normal germ cell. So it is sterile.
The answer to this is Carbon Dioxide.