These levels are classified as abiotic (those not manifest life) they belong to the atomic level and molecular level, and biotic (which manifested life) which includes levels: cell, organism, population, community and biosphere .

The molecular level: includes molecules which are formed by the association of atoms interacting via links and chemical interactions. From the diversity of atoms exist, they can form different types of molecules with different functions in nature.

Population: A group of organisms of the same species that are related to each other, who live in a particular place at a given time.