1) those who survive will have a certain allele which gives them a phenotype allowing them to have a physical advantage. for example, a giraffe may have an allele giving it a longer neck so it can reach more leaves. This allele is inherited by the offspring
You would expect an earthworm to have no exoskeleton because as you see it is very flexible and soft. Organisms with such have body parts that are divided and an earthworm do not have any visible parts on them also having an exoskeleton would not allow an organism to move like an earthworm does.
Betelgeuse is colder but more luminous
The ocean acidification is generally caused by the vast amounts of carbon dioxide that humans release in the air gettting absorbed into the ground, causing the PH of the water to rise.
Hopefully this helps!
The experimental group is the group you change from the normal. the fertilizer group is experimental