Champions
Answer: ATLANTIC
Ariel Uy

Each of the clues is an element of an ordered list. We look for the "number one" item in each of those lists. In order to extract an answer, we will need to index into each of these. Each clue is a particular number in its list, so we use those numbers to index.

CategoryClue1st ItemIndexLetter
PokemonSquirtleBulbasaur7A
Tallest MountainsDhaulagiriEverest7T
Noble GasesArgonHelium3L
Mohs HardnessGypsumTalc2A
Old TestamentLeviticusGenesis3N
PresidentsVan BurenWashington8T
Zodiac SignsGeminiAries3I
PlanetsMarsMercury4C