1. The scientific term for the inner ear is _______.   stirrup   eardrum   cochlea   Hint Half-n-half Clue   2. The nerve carrying messages from the ear to the brain is the _______ nerve.   optical   auditory   olfactory   Half-n-half Clue   3. Frogs have _______ as their hearing organs.   lateral lines   external eardrums   sensitive feelers   Half-n-half Clue   4. Pick the "odd one out" (with reference to crustaceans and molluscs).   Crab   Shrimp   Mussel   Half-n-half Clue   5. The nerve carrying messages from the nose to the brain is the _______ nerve.   gustatory   olfactory   auditory   Half-n-half Clue   6. The lateral lines of fish are sensitive to the vibrations of water.   False   True   7. Each of the hind feet of a frog has 4 toes.   True   False