Stomochord is found in(A) Urochordata (B) Hemichordata(C) Cephalochordata(D) Both A and B

The correct answer is B. Hemichordata.
Stomochord:
o The stomochord is a unique structure found in some invertebrate animals, particularly in the Hemichordata group. It is a flexible, rod-like structure that runs along the length of the animal and is thought to have some similarities to the notochord (a characteristic feature of chordates).
o The stomochord is not homologous to the notochord but is structurally and functionally similar in certain ways, providing support and involved in the digestive process.
Hemichordata:
o The Hemichordata is a group of marine invertebrates that includes species such as acorn worms. These animals possess a structure known as the stomochord, which helps support their body and may be involved in digestion. Hemichordates are considered to have a "half-notochord," hence the name "stomochord."
Urochordata:
o The Urochordata (also called tunicates) are a group of marine invertebrates that do not possess a stomochord. They are more closely related to vertebrates in terms of their embryonic development and may have a notochord at the larval stage, but not a stomochord in their adult form.
Cephalochordata:
o The Cephalochordata (also called lancelets) are another group of marine chordates. They do possess a notochord, but they do not have a stomochord.
Conclusion:
o The stomochord is found specifically in the Hemichordata group, making B. Hemichordata the correct answer.