What Is a Calendar Used For?
Calendar is a system used for calculating time. Calendars usually divide year into months and days. A year is the time it takes for the Earth to orbit the Sun once. A...
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Why are Contour Lines used on Maps?
Contour lines are used when maps are designed to show the physical nature of the land. They do this by linking all points which are the same height above sea level. The...
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When Was Braille Invented?
When Was Braille Invented? The Braille system of reading and writing was invented by a Frenchman named Louis Braille, in about 1829. It is an alphabet consisting of an...
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Why Can You Not Breathe When You Swallow?
Why Can You Not Breathe When You Swallow? You are not able to breathe when you swallow because your respiratory (breathing) system is closely linked to your alimentary...
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When Did Writing Begin?
When Did Writing Begin? Actual writing took a long time to develop. For thousands of years, men drew pictures of their activities and sent their messages in the form of...
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