Use the following description of a research study to answer questions 3-5.

A student suggests that the nicotine on smoker's hands may actually be toxic to microbes.She recruits 50 smokers and 50 non-smokers and asks them to make a hand print onto a nutrient agar suitable for the culture of a number of naturally occurring microbes.She incubates the plates for 24 hours and then measures the number of microbes growing on each plate.

3. In the study described above, the number of bacterial cultures on the agar plates is a (choose 1)

a.independent variable.

b.confounding variable.

c.dependent variable.

d.constant.

4.In the study described above, the smoking status of the participant (smoker or non-smoker) is a/an (choose 1)

1. independent variable.
2. confounding variable.
3. dependent variable.
4. constant.

5.In the study described above, the behavior of the participant (washing their hands after using the bathroom or not washing their hands after using the bathroom) is a/an (choose 1)

1. independent variable.
2. confounding variable.
3. dependent variable.
4. constant.

6.In an experiment, the group that does not receive the intervention is called:

1. The experimental group
2. The participant group
3. The control group
4. The treatment group