Can you clarify the differences between nucleophilicity (Nucleophiles change their ability to donate a pair of electrons in the process of the reaction due to polarizability. They usually attack carbon - GS)., basicity (Bases do not change their ability to donate a pair of electrons in the process of the reaction. They usually attack carbon - GS), and polarizability (Ease of separation of charges in the electric field, which makes the difference between bases and nucleophiles - GS)