The southern United States experiences periodic occurrences of severe cold and drought conditions. Which weather phenomenon most likely causes this and why? La Niña, because the jet stream is displaced southwards
La Niña, because the jet stream is displaced northwards
El Niño, because of increased upwelling of cooler waters
El Niño, because of decreased upwelling of cooler waters

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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.

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

d. cellulose and starch