What hinged surfaces on a plane's wingtips allow the aircraft to roll?

More Questions:

An Apgar score is given to what?

Which ice skater was attacked by one of her arch rivals?

How many players are there in a standard ultimate frisbee team?

What place did Dante describe as having "Abandon hope, all ye who enter here" written over its doors?

Who wrote "The Consolation of Philosophy" while in prison?

What nation's legislative body is named The States-General?

Pierre is the capital of which US state?

What island is home to nearly all the lemurs?

The Larynx is also called what?

What is at an average distance of 238,857 miles from the Earth?

What is the orbital period of Uranus?

What two pseudonyms does Howl have in the movie "Howl's Moving Castle"?

What was Ward Cleaver's occupation on the TV show "Leave it to Beaver"?

Elzie Segar created what popular character?

Which US state is known as the "Mother of Presidents and the Mother of Statesmen"?