Answer:
Experimental investigations.
Step-by-step explanation:
The process involves in experimental investigations is a "fair test" is designed and manipulation of variables, measured and controlled to collect evidence to refuse or support a formal relationship.
Experimental investigations posses a control group which does not need or receive any kind of experimental treatment.
For example, a student might conduct an investigation " Discuss the effect of light color on the growth of plants?" the student altered the variable color of light in this experiment . The student may compare green light to natural light to red light.