A student is conducting their science experiment on the effect of caffeine on dogs. He has 3 groups of test subjects. The 1st gr
oup of dogs receives plain water. The 2nd group of dogs receives 10 mg of caffeine each, and the 3rd group receives 50 mg of caffeine each. He will measure their activity levels by recording how long each dog runs without stopping, after giving them the pills. What is the dependent variable in this experiment?
In an experiment, the independent variable is the variable that the scientist/investigator purposely changes or manipulates, which isn't changed by other variables in the experiment (in this case, the amount of caffeine). On the other hand, the dependent variable is the variable that is being measured or tested during the experimental procedure (this variable is 'dependent' on the independent variable). Finally, the control group is defined as the group of individuals/subjects who do not receive the experimental treatment (in this case, the dogs that receive water).
a lack of resources would most likely decrease a population size because it will limit growth and decrease survival rates. There will also be more competition.
