Answer: The correct answer is -
d) a dominant trait that depends on the presence of only one of many dominant alleles.
Glaucoma is an autosomal dominant trait, meaning that presence of single copy of the defective gene is enough to cause the disease.
It corresponds to a group of diseases, which cause damage in the optic nerve, leading to loss of vision and if not treated, it ultimately leads to blindness.
Thus, option D) is the right answer.
Answer: Bb
Explanation: a heterozygous genotype will always result in the dominant phenotype
I'm guessing the genotypes given (RRYY x Rryy) are the offspring (if this isn't the case this answer may be wrong)
RRYY has both dominant alleles. So we can safely say that the parents are both RRYY.
For Rryy :
Rr is heterozygous (the alleles are not the same), so the parents could be:
RR x rr
RR x Rr
Rr x Rr
(if you do a small punnet square, you can double check these!)
Since yy has both recessive alleles, the parent is yy as well.