Final answer:
The flat, drowned edges of the continents are referred to as the continental shelves, which extend from the shoreline to the shelf break in relatively shallow waters and are important both ecologically and for human activities.
Step-by-step explanation:
The flat, drowned edges of thee continents are called the continental shelves. The continental shelf is the submerged portion of continent crust in relatively shallow water. It extends from the shoreline to the drop-off point marked by the shelf break. Continental shelves are significant geographic formations that are part of the continental margin, which includes the shelves, the continental slope, and the continental rise. The shelves play an important role in marine life, as they are usually rich in nutrients, and provide a home for a diverse range of marine species. Additionally, they are important for human activities such as fisheries, and can contain valuable resources such as oil and gas.