Answer: Bays are thought to be formed by plate tectonic activity and erosion of coastline.
Explanation:
A body of water irregularly surrounded by land is known as a bay. And it is quite different from a gulf.
A bay is formed this way:
• when there is an erosion of the coastline into a large body of water. E.g Guanabara Bay.
• in pre-historic era, during active plate tectonic activity where continents drifts together and as they rift apart, there is the fomation of many large bays. E.g Bengal Bay.
