The study of relationships-between organisms or between an organism and their environment

ecology is the study of the relationship between living organisms and their environment. an ecologist is someone who studies those relationships. an ecosystem is a place, such as a rotting log, a forest, or even a schoolyard, where interactions between living and non-living things occur.

explanation:

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.