Sound waves in air are a series of <span>periodic disturbances, </span><span>periodic condensations and rarefactions,</span><span> and high- and low-pressure regions. It is all of the above. The answer is letter D.</span>
Answer:
A.
Explanation:
an atom that has most of its mass is electrons.
It starts or speeds up.
Some substances need certain amount of energy in order to react with each other.
Explanation:
so sorry
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