The trophic level of an organism simply refers to the position that is occupied by an organism in a food web. It should be noted that in the next trophic level, only 10% of the energy will be available. Therefore,
There are two main types of chemical bonds that hold atoms together: covalent and ionic/electrovalent bonds. Atoms that share electrons in a chemical bond have covalent bonds. An oxygen molecule (O2) is a good example of a molecule with a covalent bond.