A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds. Chemical bonds are forces that hold atoms together to make compounds or molecules. Chemical bonds include covalent, polar covalent, and ionic bonds. Atoms with relatively similar electronegativities share electrons between them and are connected by covalent bonds. The ions then are attracted to each other. Three types of chemical bonds are important in human physiology because they hold together substances that are used by the body for critical aspects of homeostasis, signalling, and energy production, to name just a few important processes. These are ionic bonds, covalent bonds, and hydrogen bonds. A covalent bond is the strongest bond. The weakest of the intramolecular bonds or chemical bonds is the ionic bond. People can have a strong connection; similarly, some atoms can also have strong bonds between them. The Proteins we need, Carbohydrates we eat are all result of chemical bonding between atoms. The gas we use in our car is a result of chemical bonding. Oxygen (O2) we breathe is a result of the chemical bond.