Clarence grew three bearded iris plants. He put one in direct sunlight, one in
the shade, and one in the dark. The plant in the sun grew the most quickly and
looked the healthiest. Clarence concluded that bearded iris plants grow best
in the sun.
How would you evaluate Clarence's conclusion?
A. His conclusion is valid because his experiment included a control.
B. His conclusion is flawed because it is based on the appearance of the plants
C. His conclusion is flawed because he did not perform enough trails
D. His conclusion is bailed because he tested only one variable