When one life form evolves from another does the original species continue to exist?

Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between twoblack-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately howmany of the 20 offspring would have brown hair?

During convection, less dense fluid rises and denser fluid sinks.

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic