Question

A(n) ______ is a group of individuals living in the same geographical area that are capable of interbreeding and producing viable fertile offspring.

Answer 1

A species is often defined as a group of individuals that actually or potentially interbreed in nature. In this sense, a species is the biggest gene pool possible under natural conditions.

For example, these happy face spiders look different, but since they can interbreed, they are considered the same species: Theridion grallator.

http://evolution.berkeley.edu/evosite/evo101/VADefiningSpecies.shtml

Answer 2

The question does say "same geographical area." A species can be in a wide range of habitats and locations. I think the question is looking for "population" which is a group of individuals of a single species (capable of interbreeding as dejavu said) in a given area.