Explain how gravitational force keeps the earth’s yearly revolution around the sun consistent.

the reason why the planets revolve around, or orbit the Sun, is that the gravity of the Sun keeps them in their orbits, this happens because the Earth has a velocity in the direction perpendicular to the force of the Sun's pull. If the Sun weren't there, the Earth would travel in a straight line.

it cools slower in the earth meaning the crystals have more time to form than lava on the surface

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what do the different brain waves do?

explanation:

brainwaves are produced by synchronised electrical pulses from masses of neurons communicating with each other. brainwaves are detected using sensors placed on the scalp. brainwave speed is measured in hertz (cycles per second) and they are divided into bands delineating slow, moderate, and fast waves.