Answer the following question given this paragraph: 

Millions of fossils have been found since Darwin’s time. They show that evolution may occur in fits and starts. Long period of little or gradual change may be interrupted by bursts of rapid change. The rate of evolution is influenced by how the environment is changing. Today, Earth’s climate is changing rapidly. How do you think this might affect the rate of evolution?.


Q: Fossil records show that what process may occur in "fits and starts"?

 Choices:

- generation

- isolation

- variation

- evolution

A:
evolution
