A marble has to roll down a ramp and then travel a distance of 3 m. The ramp's height supported by 4 books, When the marble rolls down, it travels only 2 meters. How can the ramp be modified to increase distance the marble travels? Please help fast

If 50 ml of each of the liquids in the answer choices were poured into a 250 ml beaker, which layer would be directly above a small rubber ball with a density of 0.960 g/ml? a. sea water – density of 1.024 g/ml b. mineral oil – density of 0.910 g/ml c. distilled water – density of 1.0 g/ml d. petroleum oil – density of 0.820 g/ml