Which statement is true regarding the way in which sex chromosomes are passed on to offspring? a. Females can pass only Y chromosomes to their offspring.
b. Females can pass either an X or a Y chromosome to their offspring.
c. Males can pass either an X or a Y chromosome to their offspring.
d. Males can pass only Y chromosomes to their offspring.

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.