Here are some examples of molecules that can function as bases:

* Hydroxide ion (OH-): This is a very strong base and readily accepts protons.

* Ammonia (NH3): This is a weak base that can accept a proton to form the ammonium ion (NH4+).

* Carbonate ion (CO3 2-): This is a weak base that can accept protons to form bicarbonate ion (HCO3-).

* Amines: These are organic molecules containing a nitrogen atom with a lone pair of electrons, which can accept a proton.

* Pyridine: This is a heterocyclic aromatic compound with a nitrogen atom that can act as a base.

Key points:

* Brønsted-Lowry definition of a base: A base is a substance that can accept a proton (H+).

* Lewis definition of a base: A base is a substance that can donate a pair of electrons.

* Strength of bases: Bases can vary in their strength depending on their ability to accept protons. Strong bases readily accept protons, while weak bases accept protons to a lesser extent.

Let me know if you have any other questions!