Answer:
B. species can become extinct
Explanation:
Charles Darwin's theory of evolution by natural selection is focused around the evolution of the species, what causes the evolution, as well as their ancestry, but it doesn't focus on the extinction of the species. The extinction of the species doesn't seem to have been something of great interest to Darwin, so we can say that that theme was largely neglected in his research. That can be seen as a big flaw. The extinction of the species is very often directly connected with the evolution of other species, that become better adapted, more specialized, so they take over on the expense of the other less evolved species that dies out because it is outcompeted.
