Why do species evolve during adaptive radiation?

Adaptive radiation is the process of development of new forms of organisms from an ancestral species. When an environment changes or some new niches open, speciation from the ancestral species occurs. New species have morphological and physiological adaptations which allow them to exploit a whole range of divergent environment.

  a. chromosomes are duplicated before cell division so that each new daughter cell has a complete set

Your answer is a because that is true