There are two<span> main types of </span>wave<span> interference: constructive interference and destructive interference. Constructive interference </span>happens<span> when the amplitude of the combined </span>waves<span> is larger than the amplitudes of the single </span>waves<span>. This can occur when the </span>crests of two<span> transverse </span><span>waves overlap.
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Answer:
Star formation occurs most rapidly in the spiral arms, where the density of interstellar matter is highest.
