StemCET Logo

Biology Question 107 – NEET-UG 2026

← Back
Given below are two statements : Statement I : When any plane passing through the central axis of the body divides the organism into two identical halves, it is called radial symmetry. Statement II : In phylum Echinodermata, both adults and larvae are radially symmetrical. In the light of the above statements, choose the most appropriate answer from the options given below :

Recall the definitions of different types of symmetry found in the animal kingdom, specifically radial and bilateral symmetry.

🥷
Ninja Strategy•Verify Statement I First

Recognize that Statement I provides the correct definition of radial symmetry, which immediately eliminates options that claim Statement I is incorrect.

Step 1: Analyze Statement I: Definition of Radial Symmetry✦ Active

Statement I defines radial symmetry as a condition where any plane passing through the central axis of the body divides the organism into two identical halves. This is the accurate definition of radial symmetry.

Step 2: Analyze Statement II: Symmetry in Echinodermata○ Expand

Statement II claims that in phylum Echinodermata, both adults and larvae are radially symmetrical. While adult echinoderms exhibit radial symmetry (often pentamerous), their larval forms (e.g., bipinnaria, brachiolaria) are bilaterally symmetrical. Therefore, Statement II is incorrect.

💡 Teacher's Secret Hint

Remember that larval forms often have different symmetry than adult forms, especially in phyla like Echinodermata.

Step 3: Determine the Most Appropriate Option○ Expand

Based on the analysis, Statement I is correct, and Statement II is incorrect. This corresponds to option (3).

✦ STEM Console utilizes AI models to generate step-by-step explanations and math clues. AI can make mistakes.