Question

in a controlled experiment, how many variables are changed?
○ 5-10
○ 1
○ 2-5

Explanation:

In a controlled experiment, the key principle is to test the effect of one independent variable at a time while keeping other variables constant (controlled). This allows for a clear determination of the relationship between the independent and dependent variables. So only 1 variable is intentionally changed (the independent variable) to isolate its effect.

Answer:

B. 1