5. Researchers have found that carbon more than 8,000 years old lies deep inside a yawning sinkhole known as ‘Yongle Blue Hole’. With reference to this context consider the following statements:
- 1.Blue Holes are generally circular, steep-walled and open to surface.
- 2.The waters of the blue holes are mostly isolated from the surrounding ocean and receive more fresh water from rainfall.
- 3.Yongle Blue Hole is the deepest known marine cavern situated in the Arctic Ocean.
Which of the statement(s) given above is/are not correct?