Answer:
The correct answer is - the amount of the light received by pots.
Step-by-step explanation:
An Independent variable is a type of variable which is a change or manipulated in aspecific research or study to find the response of the dependent variable.
In this study, to find the effect of the light on the plant Mrs. Hendren uses the time period of light received by the pots of the plant in order to see the effect on the plant. So the variable that is manipulated is the amount of the light received by the pots.