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.
Many factors affect bacterial growth but the most important ones are: 1  Water -- Bacteria need water to dissolve the food they use for energy and growth. 2  Water allows the food to get into the cells, is used for the many chemical reactions necessary for life and growth, and allows waste products to escape. Energy sources such as sugars, starch, protein, fats and other compounds provide the nutrients. 2  Oxygen -- Some bacteria require oxygen to grow (aerobes) while others can grow only in the absence of oxygen (anaerobes).