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

Step 1 : Understanding the Question:
The objective is to evaluate five general biological statements about animal taxonomy and identify which of them are {incorrect}. This covers symmetry, body cavities, skeletal structures, and thermoregulation.
Step 2 : Key Formulas and Approach:
Approach: Analyze each statement against established biological facts for the specified phylum or class:
1. Symmetry rules for Echinoderms.
2. Thermoregulation in vertebrates (Cold-blooded vs. Warm-blooded).
3. Coelom types in lower invertebrates.
Step 3 : Detailed Explanation:

Statement A: Platyhelminthes have only one opening for both ingestion and egestion. This is the definition of an incomplete digestive system. This statement is correct.

Statement B: Echinoderm larvae are bilaterally symmetrical, but adult echinoderms possess radial symmetry (pentamerous). Thus, saying adult echinoderms have bilateral symmetry is incorrect.

Statement C: Aschelminthes (roundworms) are the unique phylum characterized by having a pseudocoelom, where the mesoderm is present as scattered pouches. This statement is correct.

Statement D: In the class Chondrichthyes (cartilaginous fishes), the notochord is persistent throughout life and is not fully replaced by a bony vertebral column. This statement is correct.

Statement E: Reptiles are poikilotherms, meaning they are cold-blooded and cannot maintain a constant internal body temperature. Only birds and mammals are homeothermic. Thus, this statement is incorrect.

Step 4 : Final Answer:
Based on the analysis, statements B and E are the incorrect ones. This combination is found in option (B).