Question

composition and structure of earths oceans
directions: on each line, write the term from the word bank that correctly completes each sentence. each term is used only once.
abyssal plains brackish water energy mineral
precipitation ridges salinity seawater
shelf submersibles sunlight trenches

1. the oceans were filled during tens of thousands of years with water from____________________ and possibly ice from comets and asteroids.
2. the continental margins include the continental ____________________, the continental slope, and the continental rise.
3. the large, flat areas of the seafloor that extend across the deepest parts of the ocean floor are the _abyssal plain_.
4. in areas where tectonic plates collide, the seafloor has deep ____________________.
5. in areas where tectonic plates separate, the seafloor has mid - ocean ____________________.
6. oceanographers use ____________________ to explore the seafloor.
7. physical characteristics that are used to classify the ocean into zones include water depth, temperature, salinity, density, and amount of ____________________ received.
8. water from a sea or an ocean that has an average salinity of 35 ppt is ____________________.
9. two main types of resources on the seafloor are __________________ and __________________ resources.
10. the measure of the mass of dissolved solids in a mass of water is called _salinity_.
11. freshwater mixed with seawater is ____________________.

Explanation:

1. Precipitation is water that falls from the atmosphere, which along with ice from comets and asteroids filled the oceans over thousands of years.
2. The continental margin's components include the continental shelf, slope, and rise.
3. Abyssal plains are large, flat areas on the seafloor in the deepest parts of the ocean.
4. Trenches are formed when tectonic plates collide.
5. Mid - ocean ridges are formed when tectonic plates separate.
6. Submersibles are used by oceanographers to explore the seafloor.
7. Sunlight is a physical characteristic used to classify ocean zones.
8. Seawater has an average salinity of 35 ppt.
9. Mineral and energy are two main types of seafloor resources.
10. Salinity measures the mass of dissolved solids in water.
11. Brackish water is a mixture of freshwater and seawater.

Answer:

1. precipitation
2. shelf
3. abyssal plains
4. trenches
5. ridges
6. submersibles
7. sunlight
8. seawater
9. mineral; energy
10. salinity
11. brackish water