The people of Sumer are among the earliest denizens of Mesopotamia. By about 4000 BCE, the Sumerians had organized themselves into several city-states that were spread throughout the southern part of the region. These city-states were independent of one another and were fully self-reliant centers, each surrounding a temple that was dedicated to god or goddess specific to that city-state. Each city-state was governed by a Priest King.
Answer:
The answer is C. An electron microscope.
Explanation:
Answer:
Block unwanted calls and text messages.
Don't give your personal or financial information in response to a request that you didn't expect.
Resist the pressure to act immediately.
Know how scammers tell you to pay.
Stop and talk to someone you trust.
Explanation:
The mesosphere is one of five layers of the atmosphere surrounding the planet earth. The other four layers include the troposphere, stratosphere, thermosphere, and exosphere. The mesosphere is located approximately 50km from the earth's surface and extends as far as 85km from the earth's surface. The mesosphere is located above the stratosphere and below the thermosphere. And it is third layer, located above the troposphere and stratosphere. The word 'mesosphere' is derived from the Greek words 'mesos sphaira' that literally translate to 'middle sphere'. The mesosphere is too high for weather balloons or airplanes and too low for satellites, making it difficult to study, however scientists are able to use research rockets capable of short trips for specific experiments.<span>Interesting Mesosphere Facts:Due to high atmospheric drag in the mesosphere it is not possible for research equipment such as satellites to stay in orbit.The mesosphere is very important for earth's protection. The mesosphere burns up most meteors and asteroids before they are able to reach the earth's surface.It is estimated that approximately 40 tons of meteors fall towards earth each day, and the mesosphere is responsible for burning them up before they reach the earth and cause damage to its surface.As meteors burn up they can sometimes be seen in the night's sky. Most people call them shooting stars.The mesosphere's atmosphere is low density and made up of oxygen, carbon dioxide, and nitrogen.Although most of the meteors that reach the mesosphere are burned up, some of their material hangs around afterwards, including iron and other metallic atoms.The temperature of the mesosphere becomes colder as the distance from the earth increases. The temperature can drop to -140 degrees Celsius however at its warmest level, depending on season, the temperature can reach -5 degrees Celsius.The mesosphere is the coldest atmospheric layer surrounding the earth. It becomes cold enough to freeze water vapour in its atmosphere into ice clouds. These ice clouds are blue-white and are called noctilucent clouds or polar mesospheric clouds. These clouds are more visible at sunset from the earth's poles.The mesosphere experiences atmospheric gravity waves, atmospheric tides, planetary waves, and strong winds that flow from north to south and east to west called zonal winds.The research rockets used to study the mesosphere are also called sounding rockets. These rockets are often made with surplus military rocket motors.A strange type of lightning occurs in the mesosphere. This lightning is referred to as 'sprites' or 'elves'.Together the layers of the atmosphere help to protect the earth from greenhouse gases, working like a blanket of insulation surrounding the planet.The atmosphere around the earth, including the mesosphere, helps to keep the earth's climate and weather patterns as regular as possible.The area where the mesosphere transitions into the thermosphere is called the mesopause. This is the coldest area of the mesosphere.<span>In the lower mesosphere the zonal winds blow from the north to the south, while in the upper mesosphere they blow from east to west.</span></span>
