Answer:
An ecosystem
Step-by-step explanation:
Ecosystem is the functional unit which contains all the individual or organism in a definite place which interacts with their physical environment and also with each other. So the ecosystem is made from interaction between living and non-living things in a specified space volume.
Ecosystem have many communities, communities are made up of many population and population is made up of many individuals/ organisms.
Organisms → Population → Community → Ecosystem
Therefore populations within California's Antelope Valley interact with their physical environment classifies the ecosystem level of life's organization.