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.
Different Size, Shape and Arrangement of Bacterial Cells. Bacteria are prokaryotic, unicellular microorganisms, which lack chlorophyll pigments. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Due to the presence of a rigid cell wall, bacteria maintain a definite shape, though they vary as shape, size and structure. When viewed under light microscope, most bacteria appear in variations of three major shapes: the rod (bacillus), the sphere (coccus) and the spiral type (vibrio).