Describe how blood is made to flow in a continuous circulation around the body with reference to the a.) the heart
b.) arteries
c.) veins

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Many organizations release indexes used to measure the development of the world's countries. as we learned in this lesson, these indexes measure many factors, from life expectancy to happiness. in your opinion, what are the three most important factors we can use to determine how developed a country might be? explain your answers in a few sentences.