Why do astronomers use astronomical units (AU) instead of kilometers (km)?(1 point)
AU is used in astronomy, while km is used in physics.
AU is used in astronomy, while km is used in physics.
AU is used for spacing, while km is used for length.
AU is used for spacing, while km is used for length.
There are no km in outer space, only AU.
There are no km in outer space, only AU.
Large distances are easier to express in AU than in km.