Environmental Science
Which three of the following choices are examples of commons?
A.) Clean air
B.) State parks
C.) A neighbor's swimming pool
D.) Personal computers
E.) The night sky

The correct answer to this question is either A)Clean air or D)Personal computers. But I highly suggest you go with D

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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.