If a country is isolated, it will have to produce everything that it needs: especially food clothes and medicine. It won't be able to specialize, but it will have to focus on satisfying the needs of the people.
If it is not isolated, it can specialize in the things that it can produce the best and fastest, and hope to exchange it for the things that it can't produce.
Iron rich minerals in rock pointed in one direction the switch to the exact opposite direction. I'd say that what supports this idea is that <span><u>Earth's magnetic field goes through pole reversals.</u></span>
Islam arrived in the inland of Indian subcontinent in the 7th century when the Arabs conquered Sindh and later arrived in North India in the 12th century via the Ghurids conquest
Atmospheric<span> Pressure and </span>Winds<span>. The heating of the Earth's surface and </span>atmosphere<span> by the sun drives convection within the </span>atmosphere and ocean<span>. This convection </span>produces winds and ocean currents<span>.
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