A mass extinction event is defined as events in which at least percent of the existing species go extinct within a -year period.

answer; i believe its (ovulation);

i think the answer is gold im not entirely sure

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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.