Answer:
Radio-wave communications signals travel through the air in a straight line, reflect off of clouds or layers of the ionosphere, or are relayed by satellites in space. They are used in standard broadcast radio and television, shortwave radio, navigation and air-traffic control, cellular telephony, and even remote-controlled toys.
Explanation:
It's not Portland or boise, so C Los Angeles!
Answer:
Alliances contributed to the start of World War I because so many alliances were being created all over the world. Most alliances would agree to protect one another if either country in that alliance got attacked by other countries. So if a country got attacked by another one, you could expect the country being attacked to be backed up by their alliance, creating future wars to commence.
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