UnScramble this Word: d n a d e l t i?

Questions

Geology This is the hardest naturally occurring substance.?

Geology What name is used to describe permanently-frozen subsoil?

Hahaha This normally has 4 legs and your butt is parked in it right now.?

Hirtory Name the first black nation to gain freedom from European colonial rule.?

History Britain and Argentina fought over these islands in 1982.?