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.
What is a worm? Of the thirty-odd phyla in the animal kingdom, at least a third are generally referred to as worms. If you include the more exotic, lesser-known phyla described as âworm-like,â itâs well over half. So, evolutionarily speaking, it might be easier to narrow down whatâs not a worm. If you think worms are relatively âprimitiveâ or simple animals, consider Riftia pachyptila, the hydrothermal vent worm.