The answer would be C valleys formed by a glaciers.
The reactants of photosynthesis are water, carbon dioxide and light energy.<span>Plants use these reactants to make the food that is essential for plant growth.</span>
Greek and plomety......................
Answer:
Controlled group does not receive the treatment. It used as a benchmark to measure how different tested subjects affected the result of the experiment.
For example, the famous experiment of whether plants grow faster with music in one room and without music in the other room. The plant in the no music room is the controlled group.