What best defines the biological concept of 'population'?

The biological concept of 'population' is best defined as the total number of individuals of a single species that inhabit a specific area at a given time. This definition emphasizes that a population comprises members of the same species living in a defined environment, allowing for interactions among individuals and providing insights into factors such as reproduction, competition, and resource availability. Understanding population dynamics is crucial for studying ecological relationships, species conservation, and the effects of environmental changes.

The other options present aspects related to biology and ecology but do not accurately capture the definition of a population. For example, discussing the "amount of living organisms in a given habitat" is too broad since it could include multiple species, not just one. "The variety of organisms present in an ecosystem" relates to biodiversity, which encompasses different species rather than focusing on the individuals of a single species. Lastly, "the geographical distribution of species" pertains to how species are spread across various regions, rather than specifically addressing the population concept, which is concerned with numbers within a localized area.