Read before you practise · 3 min
Read Molluscs by Mantle, Foot and Feeding
The mantle and muscular foot define the molluscan body plan; many species use a rasping radula to feed.
NSEB · Animal Kingdom · 3 linked questions · 100% coverage
Know this first
Living-system questions are solved by matching a structure or organism to its function, process and stated condition.
Structure · The part being namedFunction · What that part doesCondition · The situation that changes the answer
Study deeper: NCERT Biology · Animal Kingdom
Recognise the phylum
Molluscs are generally unsegmented and have a mantle, visceral mass and muscular foot. The mantle may secrete a shell. Octopus (“devil fish”) is a mollusc.
Locate the radula
The radula is a rasping feeding organ in the buccal cavity of many molluscs, such as Aplysia; bivalves are the major exception.
OlympIQ exam lens
- ✓Mantle + unsegmented body are key clues.
- ✓Devil fish = octopus = Mollusca.
- ✓Radula: buccal cavity of Aplysia; absent in bivalves.
OlympIQ trap
A shell is common but not universal; mantle and foot are the stronger body-plan clues.
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