However, the plesiosaur theory is not the only one. Many other ideas attempt to explain the sightings and "photographs." But two separate sonar surveys of the loch have not found any evidence of a creature larger than a salmon. The last survey,1 completed in 2007 by the British Broadcasting Company (BBC), involved 600 different sonar beams. Using satellite navigation systems, the team made sure every inch of the loch was searched. The team found nothing.

What is the main purpose of the paragraph beginning "However, the plesiosaur theory is not the only one"?

To discuss the kinds of crea

Question

However, the plesiosaur theory is not the only one. Many other ideas attempt to explain the sightings and "photographs." But two separate sonar surveys of the loch have not found any evidence of a creature larger than a salmon. The last survey,1 completed in 2007 by the British Broadcasting Company (BBC), involved 600 different sonar beams. Using satellite navigation systems, the team made sure every inch of the loch was searched. The team found nothing. 

What is the main purpose of the paragraph beginning "However, the plesiosaur theory is not the only one"?

To discuss the kinds of crea