Use evidence from the fact that an inclined plane is used for raising objects to answer the following question. Choose from options. "Eric is pushing a box up a ramp. He notices that it is much more difficult than it was a couple of hours earlier. This could be due to"

Select from:
(1). The box is a lot lighter than it was earlier.
(2). the box being grey.
(3). his box being more voluminous.
(4). the ramp is more high angle then it was earlier.
(4).