2 section 73 question 2 about 10 of the water that

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formed from organic matter that is transformed by the sediment. 2) Section 7.3 Question #2: About 10% of the water that evaporates from the ocean returns to it in rivers. How does the other 90% get back to the ocean? With the ocean being so large, a lot of the water evaporated into the atmosphere comes from these oceans. The water that returns to the ocean returns in many different forms. Contrary to natural belief, only 10% of the water evaporated from oceans that returns to oceans returns from the runoff of rivers, and the other 90% of the water returns in different forms. Much of that water returns in the form of rainfall into the ocean since the ocean is so big. The rest of the water that returns to the ocean is pulled toward the sea because of gravity whether it is from streams or lakes. 3) Section 7.4 Question #4: Describe how human land use is contributing to the increased flux of CO 2 to Earth’s atmosphere. Since humans have replaced many natural ecosystems with farmlands, cities, and suburbs, much of the carbon in the Earth’s terrestrial ecosystems has diminished significantly. These converted ecosystems add roughly 0.9-1.2 Pg of CO 2 to the atmosphere each year.
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4) Section 7.5 Question #1: Why is the global amount of nitrogen available to organisms ultimately limited by the rate of nitrogen fixation. The nitrogen-fixing microbes that carry out the conversions ultimately limit the amount of nitrogen that enters the atmosphere because only so much can be converted at one time. Even in times in which agricultural advancements have increased the rate at which nitrogen fixation occurs by about 40%, the amount of nitrogen available is still limited. 5) How does the burning of oil and coal increase nitrogen availability in the biosphere? When oil and coal are burned, the organic nitrogen in them is converted to gaseous nitric oxide (NO). This action increases the rate of nitrogen fixation, making the amount of available nitrogen in the biosphere even higher.
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