Question

(a) --- is an organized system of millions or billions of stars, gas, solar systems, and dust that are held together by gravitational attraction. options (colored boxes): friction (green), galaxy (blue), albedo (orange)

Explanation:

The description on the right ("an organized system of millions or billions of stars, gas, solar systems, and dust held together by gravitational attraction") matches the definition of a galaxy. Friction is a force, and albedo is a measure of reflectivity, so neither fits this astronomical system description.

Answer:

galaxy