<span>The answer is letter C.
Reflecting telescopes are more powerful than refracting telescopes. These are also called as reflectors which serves an optical telescope that uses a single or combination of curved mirrors. These mirrors then reflect light and form an image. It is designed for very large diameter objects and are mostly considered as major telescopes in the field of astronomy. They were used as an alternative for refracting telescopes during the 17th century because they suffer less chromatic aberrations than a refracting telescope does. <span>
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Easy ! EVERY element and every compound melts, then boils and becomes a gas, if you heat it to a high enough temperature. That includes iron, gold, water, salt, glass, almost any substance.