Which of the following phyla is characterized by the absence of a body cavity (acoelomate condition)?
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Correct answer: Platyhelminthes
Platyhelminthes (flatworms) are acoelomates: the space between the body wall and digestive tract is filled with solid parenchyma tissue rather than a cavity. Despite being triploblastic, they lack a true body cavity, distinguishing them from coelomates and pseudocoelomates.
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