Astudy is being done to test the effects of habitat space on the size of fish populations. different sized aquariums are set up with six goldfish in each one. over a period of six months, the fish are fed the same type and amount of food. the aquariums are equally maintained and cleaned throughout the experiment. the temperature of the water is kept constant. at the end of the experiment, the number of surviving fish are surveyed. a. independent variable: different sized aquariumsb. dependent variable: number of fish that survivedc. controls: negative controls are the food, maintenance, water temperature.

On the basis of the given information, the six goldfish are taken in distinct sized aquarium to examine the influence of habitat space on the rate of survival of the fishes. The kind and amount of food, cleanliness, and temperature are maintained similarly.  

Thus, with the help of the information one can state that:  

A. The size of the aquarium is the independent variable.  

B. The number of fish survived after six months is the dependent variable.  

C. Water temperature, the kind of amount of food, maintenance, and cleanliness of aquariums are the controlled variables or the constants.  

In the controlled experiments, there are dependent and independent variables. The independent variable will get modify generally and is compared to the control. The variable, which is determined in an experiment is considered as the dependent variable. It relies upon the independent variable of the experiment. The control group in an experiment is created similar in each circumstance in an experiment. The control group is the one, which is compared with the experimental group.