Question

which definition describes endosymbiosis best?
a symbiotic relationship in which one organism lives on the other organism and both organisms benefit
a symbiotic relationship in which one organism lives inside the other and both organisms benefit
a symbiotic relationship in which one organism benefits, while the other organism is harmed

Explanation:

Endosymbiosis specifically refers to a symbiotic relationship where one organism resides within another, and both gain benefits. The first option describes a general symbiotic relationship (not necessarily with one organism inside the other). The third option describes parasitism (one benefits, the other is harmed), not endosymbiosis.

Answer:

a symbiotic relationship in which one organism lives inside the other and both organisms benefit