Misc: the pacific ocean accounts for roughly what volume of the world's oceans?

Questions

The first ---------- dragons to breed in the western world are at the National Zoo at the Smithsonian Institute in Washington, D.C.?

Today's oldest form of horse is the Przewalski, or Mongolian Wild Horse. Survivors of this breed were discovered in the Gobi Desert in ----------?

The poison-arrow frog has enough poison to kill about ----------?

The first medical use of leeches dates back to approximately 2,500 years ago. The leech's saliva contains a property that acts as an anticoagulant for ----------?

Toothed ---------- whales live in extended family units that, for families, constitute life-long associations. They differ from baleen whales, which form only temporary bonds.?