Which term defines a community of interacting organisms and the physical and chemical factors of their environment? 

A)  lithosphere 
B)  population 
C)  ecosystem 
D)  species

Ecosystem

A community of living organisms in conjunction with the nonliving components of their environment, interacting as a system.

Interacting Organisms

Living entities that engage in relationships with one another within an ecosystem, such as competition, predation, symbiosis, and parasitism.

Chemical Factors

Elements and compounds that influence reactions and processes in biological and environmental systems.