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.
Nematode. Nematodes, also called roundworms, are members of the animal phylum Nematoda. These worms have a complete digestive system and are more complex than the flatworms (phylum Platyhelminthes) but lack a circulatory system and other advanced features found in the annelids (segmented worms).