Match the following. 1. processes initiated by people that shape earth's surface and interact with plant and animal life to create, sustain, and modify ecosystems human systems 2. activities occurring in nature that shape the earth's surface physical processes 3. processes occurring in nature that shape the earth's surface and interact with plant and animal life to create, sustain, and modify ecosystems systems 4. physical and human processes that shape the earth's surface and interact with plant and animal life to create, sustain, and modify ecosystems physical systems