the struggle between organisms to survive as they attempt to use the same limited resources

interaction in which one organism kills another for food or nutrients

any relationship in which two species live closely together and at least one benefits

a relationship in which both species benefit :) :)

a relationship in which one species benefits and the other is neither helped or harmed  :)  :I

a relationship in which one organism lives with, on, or inside another organism and harms it 

:)  :(

an organism that benefits by harming another organism

an organism on which a parasite lives

environmental factor that limits the growth and size of a population

species that have naturally evolved

species that enter new ecosystems and multiply, harming native species and their habitats

the removal of trees faster than forests can replace themselves

the growth of cities