This is a free-living (non parasitic) species of nematode which makes a good model organism for biological study because it has a small genome of only six chromosomes. It also has a short generation time of about three days (at room temperature), and is easy to grow at high densities (up to 10,000 worms on one Petri dish). C. elegans has been thoroughly studied by geneticists, developmental biologists and neurologists. The worms can be used to study genetic manipulation, gene therapy, and the molecular basis of differentiation during development. Much of the world's knowledge about aging, inheritance, and the factors which control gene expression during development comes from studying this and other nematodes. The full taxonomic classification of C. elegans is: kingdom Animalia, phylum Nematoda, class Secernentea, subclass Rhabditia, order Rhabditida, family Rhabditidae.