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 lives inside another (endo - means inside), and both organisms benefit. The first option just mentions one organism living on the other (not inside), and the third option is a description of parasitism (where one benefits and the other is harmed), not endosymbiosis.

Answer:

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