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).
The symbol for gold is Au
Material Manager or Scrub Tech. It depends on the hospital. A material manager orders supplies for the entire hospital while a scrub tech makes the supplies stocked in the operating room