What gas is exhaled by humans?

More Questions:

Which Quarterback led the Baltimore Ravens to victory in Super Bowl XLVII?

Vanilla flavoring is extracted from what part of the vanilla plant?

In the Western Union's alphabet what is the letter "C" known as?

A pub that is required to sell beer primarily from a single brewery is typically referred to as what?

The book "The Second Sex" was written by who?

Who composed the Christmas carol "Silent Night"?

Which European city is nicknamed "The Eternal City"?

Lake Champlain lies on the border between Vermont and which other US state?

What links Catalonia, Andalusia, Cantabria, Galicia?

What city named its airport after John Lennon?

According to the 1973 movie, soylent green is what?

Mr. Deeds hails from what fictional town?

What Robert Rodriguez film followed "El Mariachi"?

What band earned their first #1 hit song with "Boondocks"?

The song "(Everything I Do) I Do It for You" was the title track to which film?