A light-year measures the distance a light beam can travel in one year.
One light-year is equal to 9 500 000 000 000 kilometers. Why do scientists
use light-years to measure distances in the universe?

A) Light-years are the only practical unit for measuring the vast distances
of space.

B) Light-years tell us about the temperature, distance, and age of other
celestial bodies

C) Light-years are the most accurate form of measurement for universal
purposes.

D) Light-years measure the age of celestial bodies by determining how
bright the light is.