Vasoconstriction
Definition-The blood vessels under your skin become narrower. This decreases blood flow to your skin, retaining heat near the warm inner body.
I think the answer to your question is Magnetic.
They use their resources and habitats around them to survive.
Lethal alleles cause the death of an organism prenatal or after the birth. Lethal alleles are usually a consequence of a mutation and they can be recessive, dominant or conditional. Since the lethal dominant alleles are harmful whether they are carried in homozygous (e.g.AA) or heterozygous (e.g.Aa) form, a strong selection against them is present and thus these alleles are much more rare.