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.
Ascaris lumbricoides is the giant roundworm of humans, growing to a length of up to 35 cm. It is one of several species of Ascaris. An ascarid nematode of the phylum Nematoda, it is the largest and most common parasitic worm in humans.orphology. Learn more about this article. Adults: The roundworm Ascaris lumbricoides is the largest intestinal nematode infecting humans, with females averaging 30 cm in length (ranging from 20-49 cm) and measuring 3-6 mm in diameter. Males are smaller, ranging from 15-30 cm in length and 2-4 mm in diameter.