History

#1055 When did exams start?

When did exams start? Exams started in China in 605 AD. Modern schools, universities, and other educational institutions have complex systems of examinations. The purpose of them is to rank students, decide if people pass or fail, see if schools are teaching successfully, see if students are learning successfully, and many other reasons. There are

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#1048 When was the wheel invented?

When was the wheel invented? The wheel was invented in roughly 4200 BC, over 6,700 years ago. I have toyed with whether “invented” might be the wrong word to use here. “Discovered” might be better because there are many round things that naturally exist in the world. However, I think we can safely go with

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#1047 Why is Mexico City sinking?

Why is Mexico City sinking? Mexico City is sinking because they are pumping more water out of the underground aquifer than can be replaced. Mexico City is the capital of Mexico, and it has a population of almost 22 million people, which is over 17% of the population of Mexico. Since the beginning of the

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