1. primary type used as model.   isotope   satellite   plasticity   prototype   Hint Half-n-half Clue   2. change of form, character or circumstances.   trough   sextant   miasma   metamorphosis   Half-n-half Clue   3. substance which provides nourishment.   precipitant   nutrient   lumen   penumbra   Half-n-half Clue   4. layer of earth's crust or society.   objective   yield   stratum   psychosis   Half-n-half Clue   5. lowest point in wave; shallow receptacle.   trough   precipitant   spatula   nutrient   Half-n-half Clue   6. change or introduction of novelties.   microcosm   precipitant   innovation   quadruped   Half-n-half Clue   7. sleeplessness.   symmetry   magnitude   insomnia   transition   Half-n-half Clue