The deepest known point of the earth's surface, the Challenger Deep, lies in which trench?

The correct answer is A, Mariana Trench. The Mariana Trench lies in the western Pacific, east of the Mariana Islands, and its deepest part, the Challenger Deep, is close to eleven kilometres below sea level. Trenches of this kind form where one oceanic plate is pushed under another, a process called subduction, which is why they lie along the edges of the Pacific.

Option B, the Puerto Rico Trench, is the deepest point of the Atlantic Ocean, but it is far shallower than the Mariana. Option C, the Java or Sunda Trench, is the deepest part of the Indian Ocean and lies along the Indonesian arc. Option D, the Peru-Chile or Atacama Trench, runs along the western coast of South America, where the Nazca plate slides beneath the South American plate and raises the Andes. Each option is a real trench, so the answer rests on knowing which one holds the record.