Biodiversity encompasses the number of: a. ecosystems in a region and number of species in the ecosystem. b. ecosystems in a region, species in an ecosystem, and genes and alleles in a species. c. ecosystems in a region. d. species present in an ecosystem. e. genes and alleles in a species.

b. ecosystems in a region, species in an ecosystem, and genes and alleles in a species.

Explanation:

Biodiversity has three levels - ecosystem, species and genetic diversity. Therefore, Biodiversity  can be defined as the variability among living organisms involving terrestrial, marine, and other aquatic ecosystems, genes and alleles in a species and their ecological complexes such as diversity within species, and between species of the ecosystems.

one characteristic that is shared by all is a soft body. many

of these invertebrate animals also have an outer shell to protect their

body. oysters, clams, snails, and mussels are all mollusks. so are octopuses, squids, and slugs. mollusks live on land and in freshwater.

not sure if this what   you'r looking for would be percent composition