How has charles darwin contributed to the study of evolution?
a)he proposed the theory of natural selection.
b)he excavated and studied fossils.
c)he was the first one to use a 3-d printer.
d)he proposed the genetic relationship between species.

A)He proposed the theory of natural selection.

Explanation:

The naturalist Charles Darwin stated that through natural selection the species of living beings have evolved from a common ancestor.

Darwin conceived natural selection as the differential survival of organisms. Darwin postulated that the gradual accumulation of variations will bring changes in organisms that result in the appearance of new species.

not the best question format lol but what i think might as scale color is controlled by a single gene with two alleles, the green allele and the yellow allele. when moths that are homozygous for green scales are mated with moths that are homozygous for yellow scales, 100% of the offspring have green scales.

they deliver oxygen to the blood