Which structures deliver blood to the heart from the body?

Blood Vessels, I believe.

I think that it'll be the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium.

Explanation: Because, the pulmonary vein empties oxygen-rich blood, from the lungs into the left atrium.

it creates acid rain

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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.