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What layer of the Earth's atmosphere makes radio communications possible? Exosphere, ionosphere, stratosphere?
The ionosphere is an abundant layer of electrons and ionized atoms and molecules that stretches from about 48 kilometers (30 miles) above the surface of the Earth to the edge of space at about 965 km (600 mi). This dynamic region grows and shrinks based on solar conditions. Because of its high concentration of ions and free electrons, this region is able to reflect radio waves and makes radio communications possible.