UnScramble this Word: s s e s t l r u?

Questions

Trivia : In the first modern summer Olympic games in 1896, how many countries competed?

Trivia : What device is normally used to measure wind direction?

Trivia : What name is given to the belt of low air pressure that is located at the equator?

Trivia : What type of clouds are also known as thunderheads?

Trivia : The depiction of the Mad Hatter in "Alice in Wonderland" reflected a poisoning of 19th century hatmakers from what?