Kate gathered three boxes of the same size made of different materials: glass, clear plastic, and aluminum painted black. she placed them on a windowsill in the sun for an hour and then measured the warmth of the air in the box. in this experiment, the time of the hour is a( a. constant b. independent variable c. dependent variable d. control

Independent variable

Explanation:

The time for which the different material boxes are placed in the sunlight in order to measure the warmth inside each box is independent variable.

Independent variable can be defined as the factor which can be changed based on the experiment. It does not depends on any factor.

The dependent variable depends on the independent variable and based on this the hypothesis is either rejected or accepted.

Hence, the correct answer is option B

it may be wrong but i think its a