<span>3. digging irrigation canals.
Sumerians lived in present day Iraq which is mostly desert. Being arid with periods of rain, the region of Sumeria was difficult to cultivate crops. The Sumerians used a system of canals and gates to create watered plains with flooding and then closed them off during growing seasons. </span>
<em>Answer: What was the main reason Commodore Perry was sent to open trade negotiations with Japan?
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<em>Perry arrived in Japanese waters with a small squadron of U.S. Navy ships, because he and others believed the only way to convince the Japanese to accept western trade was to display a willingness to use its advanced firepower.</em>
To point in the direction they are heading but people just stare at something that's not there and not sure what they are pointing.
The correct answer is <span>b. an individual oxygen atom combines with an oxygen molecule
An oxygen molecule consists of two oxygen atoms and the molecule itself is the thing we breathe and need for survival. When the molecule is connected to another individual oxygen atom you get ozone. Ozone has the formula of O3 because of this. It is found around the planet and gives us protection from things such as ultraviolet light or similar things.</span>