What are two ways in which bays are thought to be formed

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.

answer called a epicycle;