You Are Interested in the Effect of Increased Carbon Dioxide

You are interested in the effect of increased carbon dioxide versus normal air on the growth of corn plants as well as the effect of green light versus full sunlight on the growth of corn plants.Your plan is to set up your experiment inside a greenhouse where you can control the environment.Which of the following is an aspect of the experiment that should be considered and controlled?

A) An increase in carbon dioxide should not result in a substantial decrease of other necessary gases.
B) All seedlings come from one uniform strain.
C) The intensity or brightness of the green light equals the intensity of the full sunlight.
D) All temperatures and available water remain the same for all plants.
E) All of the choices are important considerations.