Body Cavity & Coelom in Animal Classification — NEET
📚 Practice ConceptHow useful is the study of the nature of body cavity and coelom in the classification of animals?
Which of the following statements accurately describe the nature of body cavities in different animal groups? S1: The body cavity of a pseudocoelomate animal, such as Aschelminthes, is characterized by mesoderm being present as scattered pouches between the ectoderm and endoderm. S2: In coelomates, the true coelom is completely lined by mesoderm, a condition observed from Annelida to Chordata. S3: Platyhelminthes are considered acoelomates because their developing embryo lacks a mesodermal layer, thus no body cavity forms. S4: The presence of a pseudocoelom is an evolutionary advancement over a true coelom, allowing for more efficient organ placement and function. S5: Diploblastic animals, like Coelenterates, possess a rudimentary pseudocoelom due to the presence of mesoglea between ectoderm and endoderm.
View solution & NCERT explanation
Correct answer: A — S1 and S2 only
Let's evaluate each statement based on the NCERT text: S1: According to NCERT, "In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates, e.g., aschelminthes." (Page 39). This statement is correct. S2: NCERT states, "The body cavity, which is lined by mesoderm is called coelom. Animals possessing coelom are called coelomates, e.g., annelids, molluscs, arthropods, echinoderms, hemichordates and chordates." (Page 39). This statement is correct. S3: Platyhelminthes are triploblastic (Page 42), meaning they possess all three germ layers including mesoderm. They are acoelomates because the body cavity is absent, not due to the lack of mesoderm. This statement is incorrect. S4: The evolutionary trend in animals typically progresses from acoelomate to pseudocoelomate to coelomate conditions, with the true coelom offering advantages. Therefore, a pseudocoelom is not an evolutionary advancement over a true coelom. This statement is incorrect. S5: Diploblastic animals (e.g., Coelenterates) have only two embryonic layers (ectoderm and endoderm) and an undifferentiated mesoglea (Page 38). The absence of a true mesoderm means they cannot form a coelom or a pseudocoelom. This statement is incorrect. Based on the evaluation, only S1 and S2 are accurate descriptions. Option A correctly identifies S1 and S2 as correct.
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.