PLS HELP ASAP 50 POINTS

The two main factors keep a planet in motion are what and what?

Gravity, Inertia, and Velocity ( I decided to use three)

Explanation:

Gravity is the primary force that controls orbit and gravity works with inertia along with velocity.

Gravity, Inertia, and Velocity ( I decided to use three)

Explanation:

Gravity is the primary force that controls orbit and gravity works with inertia along with velocity.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.