For high school age students the blood types can be a useful introduction to heredity. It has been shown, for example, that if both parents are type O, their children must all be type O: it is recessive to A and to B.
Iowa Science Teachers Journal
© Copyright 1975 by the Iowa Academy of Science
Hollander, Willard F. and Miller, Wilmer J.
"The ABO's of Blood Types,"
Iowa Science Teachers Journal: Vol. 12
, Article 13.
Available at: https://scholarworks.uni.edu/istj/vol12/iss4/13