Answer:
refrigeration and gmos (this is based on research but it is souly opinion based because it all depends on what you think is the most important. please accept this answer with discretion.)
Explanation:
refrigeration because it helped improve shelflife for food all across the world.
gmos because it saved many crops from complete devastation and saved farmers from endless debt and depression (of money).
I think that C. 30 is the minimum recommended spf for sunblock.
The answer is <u><em>false</em></u>. 1 second is way too close. It's around the 3-4 second space. You'll learn this in drivers ed if you haven't already.