Final answer:
Trait variations within a species allow us to investigate the genetic basis of traits, the extent of inbreeding, and the risk of species extinction or invasion.
Step-by-step explanation:
Within-species trait variations allow us to investigate the genetic basis of population-wide traits, whether traits have a genetic basis, and the degree of inbreeding in a population. These variations provide valuable insights into the mechanisms of evolution, natural selection, and the genetic diversity within a species. Additionally, studying trait variations can help us understand the differences between individuals and populations, as well as predict the risk of species extinction or invasion through cross-taxonomic comparisons of life history traits.