This philosophy was centered around the family and drew parallels from the father child relationship to the emperor subject relationship<span />
The understanding of gravity was essential in the developmentof Albert Einstein theory of relativity. Which describe relationships between matter and motion.
Hills are easier to climb than mountains. They are less steep and not as high. But, like a mountain, a hill will usually have an obvious summit, which is its highest point. According to the U.S. Geological Survey, there is no official difference between hills and mountains.
