B. Biodiversity described
The term Biodiversity comprises all forms of life (plants, animals, microorganisms). It describes the number, variety and variability of organisms at all levels of organization, from the genetic, population, and species levels, to those of the ecosystem. Some conservation biologists like to distinguish an additional level of diversity. It refers to the cultural diversity of mankind, which is intimately linked to, and constitutes an overwhelmingly important influencing force on the biological diversity.
Going first to the genetic diversity, this is represented by variation the individuals of a population. This diversity arises from mutations and a combination of genes essentially reproducing organisms. The possible number of combinations of the genetic sequences of a given species--it might be mosquitoes or men or women--is estimated to be in excess of the number of atoms in the universe. The number of genes of the known number of the species on earth is one billion. The species have evolved because of factors of natural selection. Under this condition in an enormous pool of genetic variability within a population of individuals selecting those traits better adapted to environmental factors prevailing at a given moment and a given place occurs.
Biodiversity is usually equated to the number of different organisms present in a habitat or what people know and call life on earth.
Biological diversity encompasses all plants, animals, fungi and microorganisms. Our knowledge of the biological heritage of the planet, this is still pitifully poor, especially when we compare it with the understanding we have of either earth bound or universal physical phenomena. We can calculate with great accuracy the number of atoms in an object or in the universe or we can calculate with great precision the trajectory missile to Venus or any far off object. However, we are still very incapable of assessing, even to the nearest order of magnitude, the number of species present in our planet.