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.
Hydrogen bonding forms in liquid water as the hydrogen atoms of one water molecule are attracted towards the oxygen atom of a neighboring water molecule; generally, a proton shared by two lone electron pairs. In a water molecule (H2O), the oxygen nucleus with +8 charges attracts electrons better than the hydrogen nucleus with its +1 charge.