Scientists often use model organisms and model systems to test a hypothesis. Models allow the scientists to control specific variable and environmantal. For example, ecologists mayuse computer programs to model how human activities will affect the climate of a specific ecosystem. Cell biologists may use mice for modeling the effects of a new drug. While model provid useful information,they do not always answer the original question completely. For example,medicine that is effectivein mice should ideally be tosted in human, and ecological expeviments that are conducted using, and all other scientis, continuously design and revise their experiments to better understand how differant factors may iufluence their observation.