QUESTION: Can you think of a scenario in
which an experiment is set-up to
answer a scientific question that
might not contain a control
group?

(please help me this is due at 11 tonight)

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

"a.) well–developed vascular system."

about 40,000,000 results (0.81 seconds)  

search results

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.