I want to know the answer to the following question:
What does Darwin do to show that his theory can support many theories that could not be explained by individual creation of species?
All the background I'm provided with is that "The structure of Darwin's argument showed the influence of John Herschel, whose philosophy of science maintained that a mechanism could be called a vera causa (true cause) if three things could be demonstrated: its existence in nature, its ability to produce the effects of interest, and its ability to explain a wide range of observations.". Is that enough to answer the question?
Answer: no