What is a controlled variable?

 A controlled variable or constant variable is a variable that does not change during an experiment.

Explanation:

A controlled variable or constant variable is one which the researcher holds constant (controls) during an experiment. It is also known as a constant variable or simply as a control.The control variable is not part of an experiment itself it is neither the independent nor dependent variable but it is important because it can have an effect on the results gotten.

example of a controlled variable is temperature.

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.