Complete the following sentences about our Solar System:

1. The force that keeps planets and other astronomical bodies in orbit around the Sun is the ________________ force.
2. Two planets in our Solar System that are larger than the Earth are ________________ and ________________.
3. Our Solar System belongs to a galaxy called the ________________.

The diagram shows the highly elliptical orbit of a dwarf planet as it moves around the Sun. $W$, $X$, $Y$, and $Z$ are points along its orbital path.

Draw on this

At which of the points shown is the gravitational force on the dwarf planet greatest?

At which of the points shown does the dwarf planet have the greatest kinetic energy?

At which of the points shown does the dwarf planet have the greatest gravitational potential energy?

State the direction of the gravitational force acting on the dwarf planet when it is at point $Z$.