Answer:
This question is incomplete. It is asking to identify the following in the experiment:
Independent variable: CAFFEINE
Dependent variable: HEARTBEAT
Experimental group: POPULATION A, which were given 0.5g of caffeine
Control group: POPULATION B, which were not given caffeine
Constants: SAME TEMPERATURE, SAME AMOUNT OF FOOD, SAME TIME BEFORE CHECKING
Explanation:
Independent variable in an experiment is the variable which is changed or manipulated by the experiment. In this experiment, the independent variable is the CAFFEINE.
Dependent variable is the variable that is measured by the experiment or in other words, the variable that responds to changes made to the independent variable. In this experiment, the dependent variable is the HEARTBEAT measured.
The experimental group of an experiment is the group that receives the experimental treatment (caffeine). In this experiment, the POPULATION A of Daphnia magna, or water fleas are the experimental group because they received 0.5g of caffeine.
On the other hand, the control group is the group that does not receive the experimental treatment. In this experiment, POPULATION B did not receive any caffeine, hence, it is the CONTROL GROUP.
Constant or controlled variable are those variables that the experimenter must keep unchanged for all groups throughout the experiment, in order not to influence the experiment's outcome. In this experiment, the constants are: SAME TEMPERATURE, SAME AMOUNT OF FOOD, SAME TIME BEFORE CHECKING (2hrs)
