Measuring its costs and benefits in terms of energy spent and/or gained, mutualism: a. results in a gain for one individual and neither a gain nor a loss for the other. b. is a lose-lose interaction. c. None of the answer options is correct. d. results in a gain for one individual and a loss for the other. e. results in gain for both individuals.

Option (e).

Explanation:

Mutualism may be defined as the type of a biological species interaction in which both the species are equally and mutually benefited without casing any harm to each other. This is a type of positive interaction.

The measure of mutualism in costs and benefits, the energy spent or gained in mutualism is equal. The mutualism results in the gain of energy for both the individuals.

Thus, the correct answer is option (e).