Question

what is made when certain wavelengths of light, or colors, are given off by hot gases and can be thought of like a fingerprint for elements?
constellations
nebulae
supernovas
emission lines

Explanation:

Emission lines are unique spectral - signatures of elements. When hot gases emit certain wavelengths of light, these are emission lines, acting like fingerprints for elements. Constellations are groups of stars, nebulae are clouds of gas and dust, and supernovas are massive stellar explosions.

Answer:

emission lines