UnScramble this Word: c s i e a l l o?

Questions

which planet did john couch adams and urbain leverrier work out the existence and position of before it could actually be seen?

of what is pedology the study?

what device converts alternating current into direct current?

apart from gottfried leibniz, which famous scientist developed the many techniques of calculus in mathematics?

chlorine is derived from the greek word meaning what?