Question

why are spectral lines useful in classifying stars? (1 point)

they show the composition of a star.

they indicate a stars age.

they show the layers that make up a star.

they show a stars location.

Explanation:

Spectral lines are formed by the absorption or emission of light at specific wavelengths by elements in a star. Different elements produce unique spectral - line patterns, allowing astronomers to determine the chemical composition of a star.

Answer:

They show the composition of a star.