Which graph represents selection that may lead to reduced variation in a population?

In a relatively small iguana population the allelic frequency is tracked for three generations. webbing is a recessive allele; no webbing is the dominant allele. during one very rainy spring and summer, a flood washes all the iguana without webbed feet out to sea. by the fall, and three generations later, you have the gene pool seen here.

Which element forms the basis of all organic organisms a carbon b oxygen c hydrogen d nitrogen

Me with these questions image attached