Answer:
Please see the answer below
Explanation:
a. The roman numerals represent the various generations in the pedigree.
I represents first generation
II represents the second generation
b. The half shaded square and circle representing the parents means that both of them are carriers for the trait in question. <u>Tay-Sachs disease is an autosomal recessive inheritance, assuming the trait is represented by the allele </u><u>a</u><u>, the gentoypes of the parents would be </u><u>Aa </u><u>and </u><u>Aa </u><u>respectively.</u>
c. Still on the assumption that the disease is represented by the allele a. If offpsring II4 which happens to be free of the Tay-Sachs allele marries a person that also does not carry the Tay-Sachs disease gene, the cross will be as shown below.
AA x AA = AA, AA, AA, and AA.
<em>All the children would be free from the Tay-Sach's allele. That is, they will be homozygous normal.</em>