Which type of wave astronomers to determine the hottest stars?

Explanation:

In the electromagnetic spectrum are plenty of different waves that change their properties according with their length, energy, frequency. In this case, the hottest stars are the blue ones, because this means that they are spreading waves with a major frequency and, for instance, major energy, which means major hot.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.

the sun's light combined with the visible wavelenghts form what is called ultraviolet radiation, which are the long waves at the end of a visible light sprectrum.

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