Earth

2. a portion of a continent that is submerged under an area of relatively shallow water known as a shelf sea.
4. the introduction of harmful materials into the environment
5. a synthetic material made from a wide range of organic polymers such as polyethylene, PVC, nylon, etc., that can be molded into shape while soft and then set into a rigid or slightly elastic form
6. long, narrow depressions on the seafloor
7. formed by eruptions of volcanoes on the ocean floor.
8. a flat region of the ocean floor, usually at the base of a continental rise, where slope is less than 1:1000.

1. an opening in the sea floor out of which heated mineral-rich water flows.
3. the slope between the outer edge of the continental shelf and the deep ocean floor.
6. new ocean floor is created as the Earth's tectonic plates spread apart