Answer:
The correct answer will be option-
<u>1. Independent Variable:</u> brands of shampoo
2.<u> Dependent Variable</u>: shining of the hair
<u>3. Control:</u> sample without any treatment of shampoo.
4. <u>Constant:</u> amount of water and the shampoo
Step-by-step explanation:
In a scientific experiment, three important types of variables are studied which are:
1. Dependent Variable: The variable which has to be studied in the experiment which in the given question is the shining of the hair
2. Independent Variable: the variable which when modified control and influences the dependent variable which is brands of shampoo
3. Constant: The variable which remains same or constant throughout the experiment which is the amount of water and the shampoo
Also, the samples of an experiment are divided into two groups:
1. Experimental group: samples in which the variable to be studied is included
2. Control group: the group in which the key variable is not present and thus acts as a reference to the experimental group like the sample without any treatment of shampoo.