Question

Identify the phylum which shows the following characteristics: 
1. Animals are exclusively marine, radially symmetrical, and diploblastic. 
2. Body bears eight external rows of ciliated comb plates which help in locomotion. 
3. Digestion is both extracellular and intracellular. 
4. Reproduction only by sexual modes.

• A. Coelenterata
• B. Mollusca
• C. Arthropoda
• D. Ctenophora

Hint:

Ctenophora is known for its bioluminescence and comb-like cilia.

Answer 1

The Correct Option is D

Phylum identification based on characteristics:

(A) Coelenterate - Incorrect: While marine and diploblastic, they lack comb plates and show both sexual/asexual reproduction.

(B) Mollusca - Incorrect: These are triploblastic and show bilateral symmetry (except cephalopods).

(C) Arthropoda - Incorrect: Triploblastic with chitinous exoskeleton and jointed appendages.

(D) Ctenophora - Correct: Comb jellies match all characteristics - eight ciliated comb rows, diploblastic, marine, exclusively sexual reproduction with bioluminescence.

The correct answer is (D) Ctenophora, commonly called comb jellies or sea walnuts.

Answer 2

Ctenophora, commonly known as comb jellies, are marine organisms that use ciliary comb plates for locomotion.
They are radially symmetrical, diploblastic, and rely on both extracellular and intracellular digestion.
Reproduction in Ctenophora is typically sexual, and they exhibit bioluminescence, making them unique among marine animals.