When a planet moves around the sun

Which physical quantity is conserved when a planet revolves around the sun ?

Which physical quantity is conserved when a planet revolves around the sun?

What force is responsible for a planet to move round the sun?

The maximum kinetic energy of a planet moving around the sun is at a position Sun

The maximum rotational kinetic energy of a planet moving around the sun is at position

A planet moves around the sun. It is closest to sun to sun at a distance d_(1) and have velocity v_(1) At farthest distance d_(2) its speed will be