I'm assuming pink circle=female, and blue square=male, AA or Ai=type A, BB or Bi=type B, ii=type O, AB=type AB (duh)
1.First question (#30) is A
I-1 has two posibillities: Ai or AA
II-1 is complicated, if I-1 is Ai, then II-1 can be AA, Ai, AB , or Bi. If I-1 was AA, then II-1 can be AA or AB only. II-4 could be anything with an A, since one of its offspring with II-3 was AB. This eliminates B and C as correct answers for II-4. D has the wrong answers in terms of I-1 being AA, because I just explained what II-1 must be when I-1 is AA.
2.Second question is D
II-2 can possibly get an i allele from I-1 if I-1 is in fact Ai, but since its father is AB and can only contribute an A or B allele. Since you want an additive ii allele combo for II-2, 0.5 or 50% of the little i allele is contributed from the mother (I-1) and 0.00 or 0% is contributed from the father. II-2 has a 0% chance of being O type since 0*0.50=0 (multiply to add allele effects).
III-3 has a possibility of being O type if her mother (II-3) and father (II-4) each contributed one little i allele each. Mother (II-4)=0.5 contribution of i allele, and same for father if he has an i allele=0.5*0.5 or 0.25 chance of contribution.
You might say that III-3 could have a 0% chance of being type O, but remember that I-1 is Ai? She HAS to be Ai or else II-3 would not even exist as a B type! That means II-3 HAS to have an i allele to contribute to her daughter III-3.
If in fact II-4 was AA, then III-3 could be AB and Ai only. This is not true because II-3 and II-4 had a child that was B, so II-4 HAS TO HAVE an i allele to contribute.
If II-4 was Ai, then III-3 has a 0.25 chance of being ii, and other possibilities of being AB, Bi, and Ai.
I hope this helped!
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