Question

Select the incorrect statements from the following :
A. Digestive system in Platyhelminthes is incomplete.
B. Bilateral symmetry is a characteristic feature of adult Echinoderms.
C. Pseudocoelom is possessed by Aschelminthes.
D. Notochord is persistent throughout life in the class Chondrichthyes.
E. Members of class Reptilia maintain a constant body temperature.
Choose the answer from the options given below :

• A. A and C only
• B. B and E only
• C. C and D only
• D. B and D only

Hint:

Logic Tip: Echinoderm symmetry is a classic trap question. Always remember: Larva = Bilateral (like most animals), Adult = Radial (like a starfish).

Answer 1

The Correct Option is B

Concept:
The Animal Kingdom is classified based on fundamental features like body symmetry, nature of coelom, digestive system structure, presence of a notochord, and physiological traits like thermoregulation.
Step 1:
Platyhelminthes (flatworms) have an incomplete digestive system. They possess a single opening to the outside of the body that serves as both mouth and anus. Statement A is correct.
Step 2:
Echinoderms display a unique developmental shift in symmetry. Their larvae are bilaterally symmetrical, but adult echinoderms are radially symmetrical (specifically, pentamerous radial symmetry). Therefore, Statement B is incorrect.
Step 3:
Aschelminthes (roundworms) are characterized by having a pseudocoelom. The body cavity is not fully lined by mesoderm; instead, mesoderm is present as scattered pouches between the ectoderm and endoderm. Statement C is correct.
Step 4:
Members of the class Chondrichthyes (cartilaginous fishes) have a cartilaginous endoskeleton, and their notochord is persistent throughout life. Unlike higher vertebrates where it is fully replaced by the vertebral column, it remains a distinct structure in these fishes. Statement D is correct.
Step 5:
Reptiles are poikilotherms (cold-blooded animals). They lack the capacity to maintain a constant internal body temperature and rely on environmental heat sources. Only birds and mammals maintain a constant body temperature (homoiotherms). Therefore, Statement E is incorrect.
Step 6:
The question asks for the incorrect statements. Based on our evaluation, statements B and E are incorrect. This matches Option (2).