Final answer:
Genetic variation refers to the differences in inherited traits among individuals within a population, with mutation and sexual reproduction being key sources. The ABO blood type system is a classic example of genetic variation resulting from multiple alleles.
Step-by-step explanation:
Genetic variation describes differences in c. inherited traits among individuals within a population. This variation is crucial for the survival and adaptation of a species as it enables natural selection to increase the frequency of advantageous traits.
An important source of genetic variation is the presence of multiple alleles for a single gene. For example, in the ABO blood type system in humans, three alleles (A, B, and O) contribute to the diversity of blood types in the population. Mutation and sexual reproduction are the main sources of new genetic variations, with mutation being the ultimate source.
This diversity is observed at the molecular level where differences in DNA base pairs within alleles lead to a great range of genetic combinations and traits among individuals.