Science Olympiad Dynamic Planet Practice Test

Which of the following statements is true regarding continental shelves?

1. They are deep ocean areas far from land

2. They consist of shallow seabed close to shore

3. They are composed primarily of metamorphic rocks

4. They are devoid of marine life

The correct answer is: They consist of shallow seabed close to shore

The statement identifying continental shelves as consisting of a shallow seabed close to shore is correct because continental shelves are extensions of landmasses that occur beneath the ocean, characterized by their relatively shallow waters compared to the deeper areas of the ocean. Typically, continental shelves can extend from the coastline to a depth of about 200 meters, where they eventually drop off into the steeper continental slope. This shallow nature allows for a diverse range of marine ecosystems to thrive, as the proximity to sunlight supports photosynthetic life and creates habitats for various marine organisms. Additionally, continental shelves are often rich in resources and biodiversity, making them vital for fishing and other economic activities. In contrast, deep ocean areas far from land would relate to the abyssal plain or ocean basins, which do not represent the shallow characteristics of a continental shelf. Metamorphic rocks are not typically the primary composition of continental shelves; instead, they commonly feature sediments such as sand, silt, and clay, along with biological materials. Lastly, the notion that continental shelves are devoid of marine life is inaccurate, as these regions support a variety of aquatic species, contributing significantly to overall ocean biodiversity.