Answer:
Control of the cell cycle is necessary for different reasons. When the cell cycle are not regulated, cells could constantly undergo cell division without any form of control which will lead to cancer.
Internal regulation of the cell cycle is necessary to alert the passage of one phase to the next at a set given time. This helps in the overall metabolism of the body.
Answer:
Because each subject in an experiment has to have equal conditions to ensure the most accurate results. And water temperature is known to impact plant growth. An experiment using different water temperatures is a terribly inaccurate experiment.