I'm not 100% sure, but I'd say the availability of vaccines and medicine.
Answer:
A parent with one copy of a dominant allele and one recessive coded Ww for the widow's peak is called heterozygous for a trait and has a 50 percent chance of passing on the dominant allele to each of his or her offspring, regardless of the gene inherited from the other parent.
Explanation:
hope this helps in some way sorry if it does not
Adaptation through natural selection
I think it the answer could be a "steamy mixture of carbon dioxide and water vapor".
