Broader definitions of chemicals or chemical substances can be found, for example: the term 'chemical substance' means any organic or inorganic substance of a particular molecular identity, including â (i) any combination of such substances occurring in whole or in part as a result of a chemical reaction or occurring in nature.
The major groups of worms include various species of flatworm, annelid, ribbon worm, spiny-headed worm, and aschelminth. Worms typically have an elongated, tubelike body, usually rather cylindrical, flattened, or leaflike in shape and often without appendages.
Threadworms (Enterobius vermicularis) are small worm parasites that infect the intestines of humans. Threadworms, sometimes known as pinworms, are white and look like a small piece of thread. The adult female worm can be 8-13mm long, and the male worm 2-5mm long. Adult worms live for up to six weeks.