mutation is a sudden departure from the parent type in one or more heritable characteristics, caused by a change in a gene or a chromosome. A example of mutation is the golden ant and ant house.
Predation is when something kills and eats the other. A example of predation is a Allitgator.
parasitism is when only one thing benefits from it. A example of parasitism is leech and catfish.
Commensalism is where both benefit from each other. A example of commensalism is a mosquito.