Explain the differences between the arm of a human and the foreleg of an alligator in terms of natural selection

What's the waste product of electrons and pyruvate combining in fermentation?  

Which heredity condition causes a buildup of mucus in lungs and pancreas? a. cystic fibrosis b. heart disease c. huntington's disease d. sickle cell anemia

Anurse is caring for a 42-year-old client who is scheduled for an amniocentesis during the fifteenth week of gestation because of concerns regarding down syndrome. what other fetal problem does an examination of the amniotic fluid reveal at this time?