Darwin hypothesized that new species could appear gradually through small changes in an ancestral species. what experiment did he conduct to test this hypothesis?

He watched animals in their natural habitat and started research on them. Each animal have a unique place to live and they have all different ways to survive in their habitat. That is evolution, small changes became a huge help for these animals for their struggle to survive. He saw how animals could evolve so quickly into a new habitat, using their mental and physical skills to do that.

This is what i did 45-5=4040÷4=10so there are 10 white marbles but am not sure is just a question that am not sure