Which best describes adaptive radiation?
a. geographical isolation caused by an adaptation
b. adaptations that organisms teach each other
c. a decrease in the rate of speciation
d. biodiversity resulting from few ancestors

The correct answer is - D. Biodiversity resulting from few ancestors.

The adaptive radiation is an evolutionary process in which diversification is appearing among a species, and it starts to fill in different ecological niches.

The adaptive radiation occurs when a species starts to evolve into multiple different species. The reason for the diversification is available space in the ecologic niches. The members of the initial species, start to exhibit new behaviors, new ways of feeding, change in coloration, all in order to be better suited for a specific ecological niche.