Question

Study the following and pick the incorrect combinations.

\[ \begin{array}{|c|c|c|c|} \hline \text{S.No.} & \text{Phylum} & \text{Peculiar cells} & \text{Example} \\ \hline \text{I} & \text{Porifera} & \text{Choanocytes} & \textit{Chalina} \\ \hline \text{II} & \text{Cnidaria} & \text{Lasso cells} & \textit{Hydra} \\ \hline \text{III} & \text{Ctenophora} & \text{Cnidoblasts} & \textit{Pleurobrachia} \\ \hline \text{IV} & \text{Platyhelminthes} & \text{Flame cells} & \textit{Echinococcus} \\ \hline \end{array} \]

• A. I, II
• B. III, IV
• C. I, IV
• D. II, III

Hint:

Characteristic cells: \[ \boxed{ \begin{aligned} &\text{Porifera} &&\rightarrow \text{Choanocytes} &\text{Cnidaria} &&\rightarrow \text{Cnidoblasts (Cnidocytes)} &\text{Ctenophora} &&\rightarrow \text{Colloblasts} &\text{Platyhelminthes} &&\rightarrow \text{Flame cells} \end{aligned} } \]

Answer 1

The Correct Option is D

Step 1: Check each combination. \[ \begin{aligned} I. &\text{Porifera -- Choanocytes -- }\textit{Chalina} &&\checkmark II. &\text{Cnidaria -- Lasso cells -- }\textit{Hydra} &&\times III. &\text{Ctenophora -- Cnidoblasts -- }\textit{Pleurobrachia} &&\times IV. &\text{Platyhelminthes -- Flame cells -- }\textit{Echinococcus} &&\checkmark \end{aligned} \]

Step 2: Reason for incorrect combinations. \[ \boxed{ \begin{aligned} & II: \text{Cnidarians possess cnidoblasts (cnidocytes), not lasso cells.} & III: \text{Ctenophores possess colloblasts (adhesive cells), not cnidoblasts.} \end{aligned} } \]

Step 3: Choose the correct option. Hence, the incorrect combinations are \[ \boxed{II and III \] Therefore, \[ \boxed{(D)} \] is the correct answer.