A40-year-old multigravida's pregnancy is confirmed at 8 weeks' gestation. she says, "i can't wait another 2 months for an amniocentesis to find out whether my baby has a chromosomal anomaly like my first child." the nurse responds that she can have chorionic villus sampling (cvs) between the tenth and twelfth weeks; what is true about this test if it is performed before this time?

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.

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d

Which tool could you see a plant cell? a. a filter b. a microscope c. a microwave d. an electromagnet