The potassium 40 to calcium or argon 40 half-life is 1.25 billion years so if this half-life is displayed then the age of 1.25 billion years would be valid. Half life is the time it takes for an isotope to decay into half its' amount and which in the process is losing its radioactivity.
Think recessive phenotypes as paper and dominant phenotypes as teared paper. Once paper is teared, it can't be fixed. Not even tape. It'll just leave that mess exposed. Same with dominant phenotypes. It just takes one dominant trait to change the looks of future offspring.
If you don't tear the paper, everything is fine. Same with recessive phenotypes. As long as there's no contact with any dominant phenotypes, the looks of future offspring will change.
The correct answer is XHXH.
Hemophilia is an inherited genetic disease, which damages the tendency of the body to produce blood clots, that is, a procedure required to inhibit bleeding. Hemophilia A and B are both X-linked recessive disorders, though the females are hardly influenced.
X-linked recessive inheritance refers to a kind of inheritance in which a mutation in a gene on the X-chromosome makes the phenotype to be articulated in males hemizygous for the mutation of the gene, as they exhibit one X and one Y chromosome.
