Examine the diagram. A diagram with two bubbles and two arrows in the middle pointing opposite ways. The left bubble says, "The environment affects human behavior. Based on this diagram, which is the best explanation of why environmental problems are difficult to solve? The environmental problems are not caused by people. The environment is too complex for people to understand it. People change the environment in different ways, which causes human behavior to change. Humans are part of the environment, so they cannot have a large impact on the environment.