The basis for defining the length of a day is the fact that question 21 options: a. earth moves through 365.25 days a year in its orbit about the sun. b. earth rotates on its axis in 24 hours; i. e., it rotates 15° of longitude per hour. c. earth rotates east to west. d. earth does not rotate; rather, it revolves.

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!

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.