The correct answer is - plate tectonics.
The convection currents in the mantle, are having very high temperatures and very high pressures. Because of that, they managed to crack the crust, and thus divide the surface of the Earth in multiple peaces, or as we call them, tectonic plates. The very high pressure from bellow manages to push the tectonic plates in certain direction, and even though that movement is only a couple of cm per year, on the long term it has huge effects on everything on the planet.
Answer:
A. increased; Great Migration
Explanation:
When the migration began, 90 percent of all African-Americans were living in the South. By the time it was over, in the 1970s, 47 percent of all African-Americans were living in the North and West. A rural people had become urban, and a Southern people had spread themselves all over the nation.
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,300 kilometers (1,400 mi) over an area of approximately 344,400 square kilometers (133,000 sq mi).
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What are coral reefs?</h3>
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups.
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Coral Reefs of India:</h3>
India has four coral reef areas: the Gulf of Mannar, Andaman and Nicobar Islands, Lakshadweep Islands, and the Gulf of Kutch. Coral reefs protect humanity from natural calamities. They provide revenue and employment through tourism and recreation.
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Coral Reefs of Australia:</h3>
The reef is located in the Coral Sea, off the coast of Queensland, Australia, and is separated from the shore by a strait that is up to 100 miles wide and 200 feet deep in places. The Great Barrier Reef is the world's largest single structure built by living beings, visible from space.
Learn more about coral reefs here: brainly.com/question/10970167
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