Identify the experimental groups in the experiment?

to study the effects of common substance ont he heart rate of the tiny aquatic organism known as Daphnia, students placed a daphnia in a drop of water on a glass slide. TYhe Students then added 1 or more drops of a test substance dissolved in water to the slide, waited 10 seconds, then counted the heart rate for 10 seconds. the students used a clean slide and a new Daphnia each time... the test substances were Coffee, water, and Ethanol

I have to do a lab report and I don%26#039;t know what that question is asking or obviously what the answer is.. so please please please help me..

Identify the experimental groups in the experiment?

there are three substances you are testing here: water, coffee, and ethanol.

in ANY experiment, you will have a single control group and at least one experimental group.

the control group shows the behavior of the the daphnia under REGULAR, expected conditions.

the experimental group is the procedure that involves CHANGE. you had two experimental groups.. the coffee experiment and the ethanol experiment. in both cases, you are changing JUST ONE factor to see how it affects the heart rate. the group with the changed factor is the experimental group.

(hope this isn%26#039;t too late...)