Explain how Earth’s mass is related to its ability to have an
atmosphere.

Mass is proportional to gravity and gravity is necessary to hold an atmosphere, therefore mass would seem to be very important for the ability for a body to have an atmosphere.

Explanation:

Mass is proportional to gravity and gravity is necessary to hold an atmosphere, therefore mass would seem to be very important for the ability for a body to have an atmosphere.

This is what I learned, so I hope it helps you. :)