UnScramble this Word: t i o n h i g s?

Questions

Favoritism to relatives, especially in appointment to desirable positions?

In 1945, near the end of World War II, an important conference involving Truman, Churchill, & Stalin was held in this Polish city?

In Greek mythology, this person opened a box which contained all of the varieties of evil & set them loose on the world to afflict humankind?

Low body temperature?

no. 19 on the periodic table of elements, symbol 'k'?