Question

in a mutualistic relationship, on the other hand, both organisms in the relationship are better off because of their arrangement; that is, they benefit mutually from their interactions. for example, lichen is composed of two organisms, an alga and a fungus. the fungus acts like a sponge, holding on to water that the alga needs. at the same time, the alga is constantly converting sunlight into energy, so the fungus, which cannot perform this function for itself, benefits from a reliable energy source. lichen is, in turn, engaged in a commensalistic relationship with the tree that it grows on. in a commensalistic relationship, one organism benefits and the other organism neither benefits nor suffers. the tree provides lichen with a place to grow, but the tree is unaffected.

Explanation:

The text discusses ecological relationships (mutualism, commensalism) and interactions between organisms like lichen (alga - fungus) and lichen - tree. Biology (subfield of Natural Science) deals with living organisms, their interactions, and ecological relationships. This content fits within Biology as it focuses on biological organisms and their symbiotic relationships.

Answer:

Biology (subfield of Natural Science)