True. Smog is fog combined with other pollutants like smoke than can be from automobiles or cars.
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Answer: volcanic activity
Explanation: The vast majority of volcanic activity on the planet occurs along the mid-ocean ridge, and it is the place where the crust of the Earth is born. The material that erupts at spreading centers along the mid-ocean ridge is primarily basalt, the most common rock on Earth.
The thermocline describes D) an areas where the temperature of the ocean sharply decreases. These layer is between mixed layer and the deep water layer in the water and is a transition layer in the ocean.