Answer: I believe the question being asked upon is the 5.2.5 Quiz: Interactions in Ecosystems, which the answer would be, by drinking and by eating other living things, or species.
Explanation: Animals rely on rivers, lakes, and streams for water, which is apart of over environment. Furthermore, animals contain nutrients and water. Therefore, the answer would be, by drinking and by eating other living things. As a student, I read the study, or text, the study goes more in depth regarding the answer to this question in pages 11-18. Have a good day, and make sure to study! ♡︎ P.s. Also added a picture!