Sagot :
It is gravity
Explanation:
The most remarkable and unexpected fact about falling objects is that, if air resistance and friction are negligible, then in a given location all objects fall toward the center of Earth with the same constant acceleration, independent of their mass. This experimentally determined fact is unexpected, because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavy ones.
Answer:
Answer #2: Gravity is the cause why the object fell on the ground.
Answer #3 - 5: Because ballpen is heavier than the paper which is the cause why it fell first than the paper. On the other side, paper is so much lighter to the ballpen and also flat which made that the gravity to slowly pull it down. While the ballpen is long and allows the air to go through it which makes the gravity easier to pull it downward.
Explanation:
I hope I helped you ☺️