@Jason12?
What do you mean by "work"? They lie on the same chromosome ("linked" on the same chromosome) if that's what you're asking.
@Reus
I'm confident in saying that B is not an example of homeostasis. In this case, homeostasis would be the body producing its own sweat in response to heat. However, the situation in option B is that the pool provides the water on the skin - your body is not producing its own sweat.
As for D, I'm unsure. Maybe because there is no signal pathway (receptors, effectors etc) and the changing of the skin is a passive process that doesn't involve a control centre?
@MM1
We use PCR to amplify DNA to:
- amplify small amounts of fossil DNA
- make copies of genes for insertion into other cells
- forensic testing
A multiple allele system is when there are more than two possible alleles. The human ABO blood system is an example of this.