Q. What are low islands surrounding a deep central depression?
Answer: Atolls
Notes: Atolls are low islands surrounding a deep central depression. They are ring shaped islets that consist of coral reefs and surround a body of water called Lagoon, that are approximately 160 feet deep.

This question is part of 40000+ General Studies MCQ Series Course on GKToday Android app. Question Number: 92 in Oceanography - Major Oceans, Ocean Bottom Relief, Ocean Deposits in above course in App.