Nematodes (or roundworms), are generally slender worms, circular in cross section. They are remarkably uniform in structure but vary a lot in size and way of life. Some live as parasites in other animals, some are parasites of plants, and some live free in soil, marine mud and decaying organic matter.
The eukaryotic organelle containing DNA together with transcriptional machinery. DNA is organized into chromosomes. Prior to cell division chromosomes are replicated and then condense, at which time the nuclear membrane breaks down.