Answer:
Based on the provided data, the six goldfish are placed in aquariums of varying sizes to assess how living space impacts their survival rates. The food type and quantity, sanitary conditions, and water temperature are kept consistent across the board.
Consequently, from this information, one can conclude that:
A. The independent variable is the aquarium size.
B. The number of fish remaining after six months represents the dependent variable.
C. Water temperature, food type and quantity, upkeep, and cleanliness are the controlled variables or constants.
Controlled experiments include both dependent and independent variables. The independent variable is usually the one that is altered and compared against a stable control. Meanwhile, the dependent variable, which is measured in the experiment, relies on the independent variable. The control group in an experiment is kept constant and is used for comparison with the experimental group.
The final choice seems to be the last one, but I think it could also be the first one
