Seafloor spreading at midoceanic ridges is how scientists first discovered the periodic reversal of what?

More Questions:

In 1988, who were admitted at Wheaton College for the first time?

Christopher Cockerell is best known for invented what?

Who shocked the public with his 1863 painting "Luncheon on the Grass"?

What musical is based on a series of children's books by P.L. Travers?

Which country's capital city lies on the River Aar?

Saint Petersburg is located on which river?

Lake Tiberias is more commonly known as the Sea of what?

Our galaxy is commonly known by what name?

Who recorded "The Fool on the Hill" in 1968?

In The Simpsons, what is the name of the Springfield football team?

In what state was the TV show "B.J. and the Bear" set?

The Zimmermann Telegram resulted in US entry into what war?

What year was the first patent for a pencil sharpener applied for?

What is the ninety-ninth element in the standard periodic table?

What year did Beethoven finish composing Symphony No. 9?