Answer:
Astronomers used the cross-staff for measuring the angle between the directions of two stars. ... Ships' officers used it to measure the elevation angle of the noontime Sun above the horizon, which allowed them to estimate their latitude
Explanation:
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The United States experiences eruptions two or three times a year. Most of them occur in Alaska.
A volcanic eruption refers to the situation where magma is released from a volcano. Volcanic eruptions can be explosive and very dangerous. These eruptions produce lava flows, ash and pyroclastic density currents. destructive. People have died from volcanic blasts. Volcanic eruptions can cause severe threats to health through activities like floods, mudslides, power outages, drinking water contamination, and many more hazardous situations.
More than 1,500 volcanoes have erupted in the past 10,000 years. And among these, about 10 percent have been found occurring in the United States. Most of these volcanoes are found in the Alaska Peninsula.
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Cold fronts appear in areas of large temperature and air pressure decrease, whereas warm fronts appear in areas of Temperature and air pressure increase.
<h3>What are cold fronts?</h3>
Cold fronts are masses of atmospheric air that exert pressure on light warmer air masses, which then tend to rise in the atmosphere.
Cold fronts can be diagrammed in weather maps as blue lines and different triangular forms with sense to the region where they move.
In conclusion, cold fronts appear in areas of large temperature and air pressure decrease, whereas warm fronts appear in areas of Temperature and air pressure increase.
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The answer would have to be A.
