Explanation:
For any enthalpy change in a chemical reaction, (exothermic/endothermic), the activation energy must be reached so as to break the strong chemical bonds between the reactant molecules.
So the similarity of the planets and the dwarf planets are they are both mostly round because they have sufficient gravity to flatten their own surfaces into a sphere. The differences are that planets are big enough to clear the whole region of space where they orbit the sun whereas dwarf planets do not.
Electrical synapses, I believe.