The modern working definition of a gene is a portion (or sequence) of DNA that codes for a known cellular function or process (e.g. the function make melanin molecules). A single 'gene' is most similar to a single 'word' in the English language.
Polar covalent bonds hold the actual hydrogen and oxygen atoms within the molecule of water but if you meant what holds water together as a liquid then that is called hydrogenâ¦ bonding between molecules, a type of dipole interaction.
Opposite charges attract one another. The slight positive charges on the hydrogen atoms in a water molecule attract the slight negative charges on the oxygen atoms of other water molecules. This tiny force of attraction is called a hydrogen bond. This bond is very weak. Hydrogen bonds are formed easily when two water molecules come close together, but are easily broken when the water molecules move apart again.