Caenorhabditis Elegans, commonly known as the roundworm, is a free-living, transparent nematode with thin, tapered, unsegmented body, about 1 mm in length. Caenorhabditis Elegans contains 302 neurons and harbors approximately 20,470 protein-coding genes which can produce highly plastic behavior, including non-associative and associative learning and memory for mechanical, thermal, and chemical cues. It normally lives in soil and eats bacteria such as E. coli. Caenorhabditis Elegans is a simple invertebrate and a standard model organism for a great variety of genetic investigations, being especially useful for studying developmental biology, cell biology and neurobiology.