Which Order of Prenatal Events Is Correct

Multiple Choice

Which order of prenatal events is correct?

A) the heart begins beating, implantation occurs, bone cells appear, the ectoderm forms
B) the ectoderm forms, bone cells appear, the heart begins beating, implantation occurs
C) bone cells appear, implantation occurs, the heart begins beating, the ectoderm forms
D) implantation occurs, the ectoderm forms, the heart begins beating, bone cells appear