Ecology.
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<Li> Organismal  ecology  studies  how  an organism meets environmental
challenges.
<Li> Population  ecology  focuses on factors affecting many individuals
of a species live in an area.
<Li> Community  ecology  deals  with  the  array of other species in an
area.
<Li> Ecosystem  ecology  emphasizes  energy  flow  and chemical cycling
among biotic and abiotic components.
<Li> Landscape ecology deals with arrays of ecosystems and how they are
arranged in a region.
<Li> Global  ecology  examines the influence of energy and materials on
organisms across the biosphere.