One side of a seesaw carries a 21kg mass four meters from the fulcrum and a 25.5kg mass two meters from the fulcrum. To balance the seesaw, what mass should be placed nine meters from the fulcrum on the side opposite the first two masses? a. 36 kg
b. 18 kg
c. 45 kg
d. 12 kg
e. 15 kg​

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

hope this ! this is not copied! search it up, it's free of plagiarism!

the rearrangement of particles in a physical change. hope this