Levels of Animal Body Organisation — NEET Biology
📚 Practice ConceptThough all members of Animalia are multicellular, all of them do not exhibit the same pattern of organisation of cells. For example, in sponges, the cells are arranged as loose cell aggregates, i.e., they exhibit cellular level of organisation. Some division of labour (activities) occur among the cells. In coelenterates, the arrangement of cells is more complex. Here the cells performing the same function are arranged into tissues, hence is called tissue level of organisation. A still higher level of organisation, i.e., organ level is exhibited by members of Platyhelminthes and other higher phyla where tissues are grouped together to form organs, each specialised for a particular function. In animals like Annelids, Arthropods, Molluscs,
Which of the following statements regarding the levels of organization in animal phyla are NOT correct? S1. All multicellular animals invariably exhibit at least the tissue level of organization. S2. Platyhelminthes are the first group of animals to exhibit the organ system level of organization. S3. Coelenterates show a cellular level of organization with some division of labor among cells. S4. Annelids, Arthropods, and Molluscs all exhibit the organ system level of organization. S5. Ctenophores share the same level of organization as sponges.
View solution & NCERT explanation
Correct answer: C — S1, S2, S3 and S5
Let's evaluate each statement based on NCERT: S1. Not correct. Sponges are multicellular but exhibit a cellular level of organization, not at least tissue level. (NCERT: "in sponges, the cells are arranged as loose cell aggregates, i.e., they exhibit cellular level of organisation.") S2. Not correct. Platyhelminthes exhibit the organ level of organization. The organ system level of organization is first observed in phyla like Annelids, Arthropods, Molluscs, Echinoderms, and Chordates. (NCERT: "organ level is exhibited by members of Platyhelminthes... In animals like Annelids, Arthropods, Molluscs... This pattern is called organ system level of organisation.") S3. Not correct. Coelenterates exhibit tissue level of organization, not cellular level. (NCERT: "In coelenterates... cells performing the same function are arranged into tissues, hence is called tissue level of organisation.") S4. Correct. Annelids, Arthropods, and Molluscs are explicitly mentioned as exhibiting the organ system level of organization. (NCERT: "In animals like Annelids, Arthropods, Molluscs... This pattern is called organ system level of organisation.") S5. Not correct. Ctenophores exhibit tissue level of organization, while sponges exhibit cellular level of organization. (NCERT: "Ctenophores... with tissue level of organisation." and "in sponges... cellular level of organisation.") Therefore, statements S1, S2, S3, and S5 are not correct. The final answer is C.
What does NCERT say about Though all members Animalia?
Has this concept appeared in NEET?
Which chapter is this from?
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.