useless trivia: What Word Means: Warms Up - Plural Of Heat, A Stage Of A Competition?

Questions

Some soft drinks are made sweeter by adding?

Albert Einstein was thought to be suffering from dyslexia, as he couldn't speak properly until he was _____ years old?

The Chinese used fingerprints as a method of identification as far back as AD?

Sir Isaac Newton was only _______ ______ years old when he discovered the law of universal gravitation?

A flush toilet exists that dates back to?