Answer:
b. red-green color blindness and hemophilia.
Explanation:
Two types of gene determine sex of human. The X-chromosome and the Y -chromosomes.They are known as heterosomes, because they are different, Unlike other somatic chromosomes which are known as autosomes because of similar morphology.
If a gene is found on X chromosome, but with no corresponding match on Y-chromosomes ; that is not available on Y chromosome, the gene said to be a sex-link-gene.
Therefore diseases transmitted by this gene are said to be sex-linked diseases, that is it is linked to the gender or sex- that the chromosomes, will determine.(since pairing of XY-male and XX - female).
Thus if the sex-linked gene is present on X-chromosome, of both parents, the girl child inherits the sex-linked diseases. One defective X-chromosomes from each parent.
However, if the gene is present on the inherited X-chromosomes of the mother, and the Y chromosomes of the father, the male child is Sex-linked.
In a carrier mother with one X-chromosomes of sex-linked disease and the other of free of sex-link, if the girl child inherits this sex-linked gene from the mother, and normal X- chromosomes from the father, the girl child who now has one sex-linked gene, and other normal X-chromosomes of the father is said to be a carrier. Thus such a girl child is not affected, but can pass the defective gene in subsequent generation provided she gets married to a man with sex -linked gene.
Men are not carriers of sex-linked diseases because, men only have 1 X-chromosomes, the Y-chromosomes is very weak, smaller than the X, and therefore can not bear the sex-linked genes. This explains the reasons why most sex-linked characters of females are usually inherited from fathers.
