The lowest level of environmental complexity that includes both living and nonliving factors is thea: biome b: community c: ecosystemd: biosphere

Ecosystem

An ecosystem is a community made up of living organisms and nonliving components such as air, water, and mineral soil. Ecosystems can be studied in two different ways. They can be thought of as interdependent collections of plants and animals, or as structured systems and communities governed by general rules.

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.