I think the answer is mutualism.
because mutualism means that the two species benefit each other.
A catalyst is a chemical that increases the rate of a chemical reaction without itself being changed by the reaction. The fact that they aren't changed by participating in a reaction distinguishes catalysts from substrates, which are the reactants on which catalysts work. Enzymes catalyze biochemical reactions.
Protostars are less dense than other stars.
Explanation:
Protostars are very young ‘stars’ made from hydrogen clouds that are beginning to coalesce and collapse under their weight. The hydrogen has not even begun fusing. Therefore, they are mainly made of hydrogen which is the lightest element in the universe.
Stars, however, have begun fusing hydrogen to other heavier elements like helium, carbon, oxygen, and iron. The elements are much heavier than hydrogen making other stars much denser than protostars.
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The ability to do work or cause change is
Energy
Salt water is considered to be a solution