Answer:
The second answer choice.
Explanation:
Genetic variation must be the answer as the plants were grown in the same conditions. Therefore, the only source of variability might be genetic variation.
The first choice is not the answer because Genetic factors cannot cause the environment around the plant to change.
The third choice is not the answer because the Environmental factors are the same, and if they were really to cause a mutation, all three plants would mutate.
The fourth is the same reason as the third: if environemnt conditions affected the flower, all three plants would change color since they were all grown in the same environemnt, not just the one we see in the results.
