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.
Pinworms and Threadworms. About threadworms, pinworms, and seatworms. There are a number of types of worm (helminth) infestations that humans are susceptible to. Of these, the most common by far is the Enterobius vermicularis, also known as the threadworm, pinworm or seatworm. Do not confuse it with the Strongyloides stercoralis worm that is sometimes also referred to as threadworm but is a very different type of worm.