Which term is used to describe a fact that has always been observed true but could at some future time not be observed as true.

This is what we call a theory in science in its strictest sense. When we're talking about theories in science we're talking about culminations of datasets that have up to this point always been true, however, we're leaving the posibility that they will once be wrong still open. 

Competition. interaction among organisms that compete for the same natural resource (food, shelter, water, space) in an ecosystem. predation. an interaction in which one organism kills another for food. predator. prey. symbiosis. mutualisum. commensalisum. parasitisum.

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