D A population bottleneck temporarily reduces the population size by one-tenth.
8 Recently, bears have been found in the Arctic Circle that are hybrids between
bears and
polar bears. Which type of isolating mechanism usually keeps these
from
producing offspring?
A mating and breeding in different habitats
B production of a nonviable embryo or fetus
C inability of sperm to reach the egg during mating
D failure of the fertilized egg to implant in the uterus