What role do genetic factors play in causing birth defects?

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

If jane has the blood type ab and marries john who has type o blood what are the possible phenotypes of their first kid?

The illustration shown is an ovum, a female sex cell. a mutation in this cell may be passed to the woman’s offspring during a) birth. b) mitosis. c) dna replication. d) sexual reproduction