Continue with the subject of blood types.
Explain how the blood types are determined by antigens on red blood cells.
Introduce a brief lesson on Mendelian genetics, the terms dominant, recessive.
Explain how two genes are needed for a trait to express and how they are inherited.
Introduce the genotypes of the ABO blood typing system, and which are dominant.
Discuss transfusion and why introducing a different type of blood will lead to agglutination and death.
Present a series of blood type possibilities in a fetus given the parents' blood types.