Doug has filled a long tray with an even layer of sand. doug then uses two bricks to prop up one side of the tray. next, doug uses a watering can to pour water onto the high side of the tray. what natural process is he making

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

report!

explanation:

physics means: "the branch of science concerned with the nature and properties of matter and energy. the subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms."

i think its c if i'm wrong