In the 1800s, how did darwin explain the origin of species? species originate through geographic separation. species originate through adaptation by natural selection. species originate through paleontological changes. species originate through changes in allele frequencies.

In the 1800s, Darwin explains the origin of species. As species originate through adaptation by natural selection.

Species originate through adaptation by natural selection

Explanation:

The Origin of species through natural selection is a pioneering scientific effort of the British naturalist Charles Darwin in England. Darwin's theory is that organisms are gradually evolving through what is called "natural selection"

It is a process in which organisms change due to hereditary changes in physical or behavioural traits. Changes that allow the body to better adapt to its surroundings, help it survive and have more offspring.

"d.) carbon dioxide and hydrogen sulfide"