Goitre is mostly caused by what deficiency?

More Questions:

Where on your pants can you often find the initials YKK?

In 1976-1977 season in 80 games, the Montreal Canadiens set the NHL record for how many points in a season?

What was Tchaikovsky's first ballet?

What US state is the source of the Arkansas, Platte, and Rio Grande rivers?

Which US state is nicknamed the "Ocean State"?

What blood vessels carry blood towards the heart?

What constellation is Polaris located in?

Who wore "yellow feathers in her hair and a dress cut down to there"?

What was the real first name of David Soul's "Hutch" on "Starsky and Hutch"?

What is Mr. Snuffleupagus's given name?

What song was used as the theme for the Three Stooges"?

What was created almost 7,000 years ago by the eruption of Mount Mazama?

What did American patriots dump into Boston Harbor in 1773 to protest British import taxes?

Alan Shepherd was scheduled to command Apollo 13 before switching missions with what astronaut?

Daniel Keyes wrote which 1959 Hugo-award winning Science-fiction novel?