Ecosystems usually become balanced by natural controls, including natural selection. a balanced ecosystem is one in which the first organism on the food chain must outnumber the subsequent organisms on the food chain. there are an equal number of organisms at all levels of the food chain. the last organism on the food chain must outnumber the first organism on the food chain.

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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.