Bill Gates formed a company to sell a computerized traffic counting system to cities, which made $20,000 its first year. Business dropped sharply when customers learned Gates was only _______ years old?
Colonel Waring, New York City Street Cleaning Commissioner, was responsible for organizing the first rubbish-sorting plant for recycling in the United States in?
Cooking and salad _____ could lubricate machinery, such as cars and boats, according to Penn State chemical engineers?
Dating back to the 1600s, thermometers were filled with ______ instead of mercury?
Early models of vacuum cleaners were powered by?