Question

Structurally Centrale diatoms are ``X'' symmetrical and Pennales diatoms are ``Y'' symmetrical. `X' and `Y' respectively are

• A. X - Bilateral, Y - Radial
• B. X - Radial, Y - Bilateral
• C. X - Polyhedral, Y - Radial
• D. X - Helical, Y - Bilateral

Hint:

{C}entrales = {C}ircle = {R}adial. {P}ennales = {P}en-like/Elongated = {B}ilateral.

Answer 1

The Correct Option is B

Step 1: Classification of Diatoms:
Diatoms (Bacillariophyceae) are broadly classified into two orders based on symmetry:

• Centrales (Centric diatoms): These are circular, discoid, or cylindrical in shape. They exhibit Radial symmetry.
• Pennales (Pennate diatoms): These are elongated, boat-shaped, or needle-like (e.g., \Pinnularia, \Navicula). They exhibit Bilateral symmetry.

Step 2: Match Variables:
X (Centrale) = Radial.
Y (Pennales) = Bilateral.
Step 3: Final Answer:
Option (B) matches this sequence.