Given a scientific question, generate a correct answer to it.

Input: Consider Input: Which process helps provide cleaner water for agriculture?

Output: process of desalinization

Input: Consider Input: A problem with using food chains to describe ecosystems is that some organisms can feed on or be consumed by species from more than one of what level?

Output: trophic level

Input: Consider Input: What are the large segments of the earth's crust that ordinarily move very slowly?
Output: tectonic plates