Question

An experiment was designed to investigate if caffeine would raise the heartbeat of water fleas. Two groups of water fleas were used. Both groups were fed the same food, received the same amount of light, and had their temperature maintained at 20°C. Every two hours, water fleas from both groups were selected and their heartbeats were checked. The fleas of group 1 were given caffeine five minutes before their heartbeat was checked. The fleas of group 2 were given nothing. What is the Control Variable?

Answer 1

Answer:

That is administered and controlled

Step-by-step explanation:

A variable is the condition or a product that may vary without the influence of any investigator. Such variables can be found abundantly in our daily lives, ranging from air to sunlight. Controlling such variables ensures the limitation of their influence on the outcome of an experiment. In connection to this experiment, the variables that are controlled are the mineral content in the water, the  amount of bacteria food, the amount of light and the the constant temperature of 20 degrees C.

If not administered or these variables controlled, the experiment would not clearly explain the impact of caffeine on the heart beat of the water fleas as other variables may have influenced it. Thus variables are controlled to study the singular impact of any agent or effect.