These energy exchanges are not changes in kinetic energy. They are changes in bonding energy between the molecules. If heat is coming into a substance during a phase change, then this energy is used to break the bonds between the molecules of the substance. The example we will use here is ice melting into water.
D. Velocity because it describes a speed and direction
The gas that gives Neptune and Uranus its amazing blue color is methane
Nuclear fusion is a reaction in which two or more atomic nuclei come very close and then collide at a very high speed and join to form a new nucleus. This process is important to stars because they get their energy from the nuclear fusion process
I’m pretty sure it’s Radioactive decay