Cara and chuck were looking at pond water through a microscope. they saw small square crystals in their slide. cara wondered what it was. chuck said it could not be any living thing because it was not round. b) moving. c) small enough. d) made of cells.

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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.

the correct answer is d