Answer the following question given this paragraph: 

Some bacteria depend on other organisms for survival. For example, some bacteria live in the roots of legumes, such as pea plants ( Figure below ). The bacteria turn nitrogen-containing molecules into nitrogen that the plant can use. Meanwhile, the root provides nutrients to the bacteria. In this relationship, both the bacteria and the plant benefit, so it is known as a mutualism .


Q: In biology, a relationship that benefits both entities is known as what?

 Choices:

- naturalism

- altruism

- predatory

- mutualism

A:
mutualism
