1. navigational instrument for angular measurements.   serendipity   sextant   placebo   terminology   Hint Half-n-half Clue   2. combining elements to produce whole system.   vent   synthesis   virus   parameter   Half-n-half Clue   3. record of daily activities.   spectrum   log   molecule   symmetry   Half-n-half Clue   4. optical illusion due to atmospheric conditions.   vortex   mirage   inconsistency   pestle   Half-n-half Clue   5. finding the total or summary.   summation   objective   innovation   serendipity   Half-n-half Clue   6. discovery by accident.   pachyderm   suture   strut   serendipity   Half-n-half Clue   7. substance which provides nourishment.   inconsistency   torque   spatula   nutrient   Half-n-half Clue