(N/A) Biodiversity refers to the variety and variability of life on Earth. It is typically measured by three hierarchical levels of biological organization:
$1$. Genetic diversity: It refers to the diversity in the number and types of genes as well as chromosomes present in different species and the variations in the genes and their alleles in the same species.
$2$. Species diversity: It refers to the variety of species within a region. The number of species per unit area is called species richness.
$3$. Ecosystem diversity: It refers to the diversity at the level of the ecosystem,such as the variety of habitats,biotic communities,and ecological processes in the biosphere.