Species can vary in several ways. Which of the following is one of Darwin's ideas that was accepted by most scientists of his time due to the large number of fossils being discovered at that time?

Due to the large number of fossils being discovered at that time Darwin proposed that species change over long periods of time.

Explanation:

The theory of Darwin was that the species change in accordance to their environment, thus they develop advantageous traits so that they can be more competitive.