Explain why offspring of plants exposed to radiation may have characteristics not found in the original population.

Radiation can damage DNA. This could result in a change in the proteins which make up the plant's physical structure.

For example, a plant might have a gene for purple pigment which makes its flowers purple. Radiation might change the DNA sequence so that the directions for making the purple pigment tell it to stop prematurely, and the result might be white flowers rather than purple flowers.