A zombie apocalypse wipes out almost the entire human species before the zombie threat is eliminated. Only a group of 100 people who were at a family reunion on an uninhabited island survived. They returned to the mainland completely unaware of what had happened to everyone. Answer the following question(s) regarding the few survivors who now begin to rebuild the human population. Certain traits will have been lost from the gene pool forever. This loss of diversity in a reduced population is called

Genetic Bottleneck.

Explanation:

Genetic bottle neck is a phenomenon in which a large part of population is lost within a very short period of time. This evolutionary event may occur as a result of certain natural calamity, habitat destruction etc. This phenomenon radically changes in the allele frequencies and sometimes the recessive traits establish themselves in the population.

In this case also certain traits are lost and diversity is reduced so it is an  instance of genetic bottleneck.

they deliver oxygen to the blood

a. to encourage apoptosis