<u>Answer:</u>
Earth's climate has changed naturally over the past 650,000 years, moving in and out of ice ages and warm periods. Changes in climate occur because of alterations in Earth's energy balance, which result from some kind of external factor or "forcing" an environmental factor that influences the climate.
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<u>Explanation:</u>
*Hope this helps*
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Ok I may be young but combine the two reactions to create a compund
Radiography techs are trained to operate medical equipment that uses X-rays and other types of radiation. Ultrasound techs, referred to professionally as diagnostic medical sonographers, operate equipment that uses high-frequency sound waves to create images.
(Credits to google)