The United Illuminating Company (UI) is a regional electric distribution company based in Orange, Connecticut.
Although generally not visible to the naked eye, organisms composed of prokaryotic cells still dominate the earth. Their collective mass is at least 10 times greater than the mass of all eukaryotes combined. Organisms composed of prokaryotic cells are classified into 2 main groups: archaea and bacteria. Archaea most closely resemble the first primitive cells on our planet.
The domain Eukaryota includes all organisms that have membrane-bound structures called organelles, which include the nucleus, mitochondria and chloroplasts. The most diverse group in Eukaryota is the protist kingdom. Some scientists do not think that the protists should be lumped together in one kingdom. The other two domains contain organisms that do not have organelles. These organisms are called prokaryotes and consists of bacteria.