A scientist shines ultraviolet light on a colony of blue colored bacteria. She then places colonies of the bacteria in separate Petri dishes. After allowing the bacteria to replicate for several generations, the scientist observes that some of the dishes now contain colonies with purple and red colored bacteria. What can be concluded from this observation?

A.
Asexual organisms will undergo genetic changes if placed in a Petri dish.
B.
Organisms undergo mutations to become better suited to their environment.
C.
Genetic changes are always harmful to organisms that reproduce asexually.
D.
Mutations lead to genetic variation in organisms that reproduce asexually.