Which is the best definition of directional selection?
a process by which two species can no longer reproduce
a process by which one of the extreme variations of a trait is favored
a process by which individuals with either extreme of a trait are favored
a process by which average individuals in a population are favored

The answer is; a process by which one of the extreme variations of a trait is favored

This directional selection is one of the types of natural selections. The others being; disruptive selection and stabilizing selection. This occurs when a particular extreme trait becomes advantageous to the environment and hence becomes favored by selection pressures. The allelic frequency of the population then changes over generations (with a higher and higher frequency of the extreme allele featuring in the population).

telophase and anaphase