A hexahedron (plural: hexahedra) is any polyhedron with six faces. A cube, for example, is a regular hexahedron with all its faces square, and three squares around each vertex. There are seven topologically distinct convex hexahedra, one of which exists in two mirror image forms.
Some bacteria that can help the environment are called decomposers. They are nature's recyclers! They return basic chemicals to the environment for living things to reuse! For example, the leaves of many trees die in the Autumn and drop to the ground.ome bacteria that can help the environment are called decomposers. They are nature's recyclers! They return basic chemicals to the environment for living things to reuse! For example, the leaves of many trees die in the Autumn and drop to the ground.
Bacteria and other microbes play the important role in environment of DECOMPOSERS, which act in the last stage of food chain. These microorganisms like bacteria cause the brea â¦ kdown of energy rich organic compounds.xample: Nitrobacter. 3. Bacteria that denitrifies nitrates (NO3-) in the soil (called denitrifying bacteria). Example: Pseudomonas denitrificans. 4. Bacteria that fixes nitrogen (called nitrogen-fixing bacteria). Examples: Rhizobium (which is symbiotic) and Azotobacter (which is free-living). 5.