Phylum Placozoa MCQs January 8, 2026September 28, 2024 by u930973931_answers 30 min Score: 0 Attempted: 0/30 Subscribe 1. Placozoa are primarily known as: (A) Simple multicellular animals (B) Jelly-like organisms (C) Flat animals (D) Marine mammals 2. The most well-known species of Placozoa is: (A) Placozoa simplex (B) Trichoplax adhaerens (C) Turritopsis dohrnii (D) Chordata 3. Placozoa primarily inhabit: (A) Freshwater environments (B) Terrestrial habitats (C) Deep-sea vents (D) Marine environments 4. The body structure of Placozoa is best described as: (A) Cylindrical (B) Radially symmetrical (C) Segmented (D) Flat and irregular 5. Placozoans primarily feed on: (A) Larger prey (B) Other marine animals (C) Algae and organic debris (D) Detritus 6. The movement of Placozoa is characterized by: (A) Swimming using fins (B) Jet propulsion (C) Burrowing into sediments (D) Gliding over surfaces 7. Placozoans reproduce primarily by: (A) Binary fission (B) Budding (C) Sexual reproduction (D) Fragmentation 8. The body of a Placozoan is composed of how many cell layers? (A) One (B) Three (C) Two (D) Four 9. A characteristic feature of Placozoa is: (A) Presence of a circulatory system (B) Ability to form shells (C) Complex organ systems (D) Lack of a true body cavity 10. The outer layer of a Placozoan is primarily composed of: (A) Nerve cells (B) Muscle cells (C) Epithelial cells (D) Ciliated cells 11. Placozoa are classified within which larger animal group? (A) Metazoa (B) Protozoa (C) Coelenterata (D) Annelida 12. The feeding process in Placozoa is characterized by: (A) Filter feeding (B) Active predation (C) Absorption through the body surface (D) Phagocytosis 13. The term “placozoan” is derived from Greek, meaning: (A) Flat animal (B) Simple creature (C) Tiny organism (D) Soft body 14. Which statement about Placozoa is TRUE? (A) They can undergo both sexual and asexual reproduction. (B) They have complex nervous systems. (C) They have a defined skeletal structure. (D) They exhibit bilateral symmetry. 15. The interior of a Placozoan is filled with: (A) Mesoglea (B) Coelom (C) Parenchyma (D) Protoplasm 16. Placozoans are known for their ability to: (A) Regenerate lost body parts (B) Form colonies (C) Swim against currents (D) Live in extreme conditions 17. The ecological role of Placozoa primarily includes: (A) Predators in marine ecosystems (B) Primary producers (C) Decomposers of organic material (D) Symbiotic relationships with coral 18. Placozoa are often found in which specific marine environment? (A) Open ocean (B) Coral reefs (C) Rocky shores (D) Tide pools 19. The body of Placozoa lacks which of the following structures? (A) Organs (B) Tissues (C) Cell layers (D) Sensory cells 20. Placozoans are believed to be one of the most: (A) Primitive multicellular animals (B) Complex multicellular organisms (C) Adaptable marine organisms (D) Colorful marine species 21. The primary method of locomotion for Placozoa involves: (A) Ciliary movement (B) Contractile muscles (C) Pseudopodia (D) Jet propulsion 22. A primary characteristic of Placozoa is: (A) Presence of gills (B) Simple body plan (C) Photosynthetic capability (D) Highly developed nervous system 23. The body of a Placozoan can often change shape by: (A) Fluid movement (B) Rapid cell division (C) External pressure (D) Muscle contraction 24. Placozoans primarily reproduce by: (A) Sexual reproduction (B) Binary fission (C) Asexual budding (D) Fragmentation 25. Placozoans exhibit which type of symmetry? (A) Bilateral symmetry (B) Radial symmetry (C) Pentamerous symmetry (D) Asymmetry 26. Placozoans are significant for studies in evolutionary biology because they: (A) Show advanced multicellularity (B) Have complex behaviors (C) Represent early branching in the animal kingdom (D) Are closely related to vertebrates 27. The cells that facilitate feeding in Placozoans are: (A) Gastrodermal cells (B) Epithelial cells (C) Mesenchymal cells (D) Ciliated cells 28. Which statement about the habitat of Placozoa is true? (A) They prefer deep oceanic waters. (B) They thrive in areas with abundant organic material. (C) They are found in nutrient-poor environments. (D) They require high light conditions to survive. 29. Placozoa are most closely related to which of the following groups? (A) Cnidarians (B) Sponges (C) Annelids (D) Flatworms 30. The first scientific description of Placozoa was published in which year? (A) 1824 (B) 1883 (C) 1970 (D) 2000