Question

1. alex wanted to find out what toothpaste made teeth the cleanest. everyday she brushed her teeth with a different product and then took a plaque test to see how much plaque was left. she used crest, colgate, close - up, and water.

\ta. independent variable (iv):
\tb. dependent variable (dv):
\tc. control:
\td. constants:

Explanation:

Step1: Identify the independent variable

The variable that is changed is the type of tooth - paste (Crest, Colgate, Close - up, water). So the independent variable is the type of toothpaste.

Step2: Identify the dependent variable

The variable that is measured as a result of the change in the independent variable is the amount of plaque left after brushing. So the dependent variable is the amount of plaque left.

Step3: Identify the control

The control is the group that does not receive the treatment (in this case, the tooth - paste). Water is used as a control as it is not a tooth - paste.

Step4: Identify the constants

Constants are the factors that are kept the same throughout the experiment. Here, the person (Alex), the time of brushing (everyday), and the method of testing (plaque test) are constants.

Answer:

a. Type of toothpaste
b. Amount of plaque left
c. Water
d. Alex, time of brushing, method of testing