AP Biology Homework, help please!!

[DearAmsterdam]

Okay I swear I have read over this 10 times and I am convinced that it's a trick question, please help me!:

An experiment on a species of small freshwater fish recorded their behavioral responses to different temperatures. Ten fish were each tested once, one at a time.

To begin the experiment, a fish was removed from a stock tank (maintained at 22 degrees Celsius) and placed in a temperature-gradient tank. After the fish had spent 30 minutes in the temperature-gradient tank , the section where the fish was located was recorded. Additional observations were recorded every 5 minutes, for a total of 7 observations per fish.

1. Identify TWO variables that were not specifically controlled in the experimental design.

[JackBean]

what about age and sex of the fishes? The oxygen level seems not to be controled as well (and is IMHO important) or basically the composition of the water

[Darby]

Seems like the stock tank water should have been used in both.

We can't tell whether the lighting was controlled, or whether the gradient was tested "backward."

There really isn't a basic control - transfer the fish without the gradient and see if they orient anyway.