In the organization of living things, a __ would include the largest number of individuals

The correct option is B) ecosystem

Explanation:

Species can be described as a group or organisms that can interbreed and produce fertile offsprings.

A population can be described as the number of a particular type of species which are living in a given area at a particular time and they have the ability to breed and produce viable offsprings.

All the different populations living in an area at a particular time make up a community.

All the living communities with all the non-living factors (abiotic factors) of an area make up an ecosystem. Hence, ecosystem is the correct option.