1 If a lot of blood leaks out, it can cause a buildup of pressure in the brain because the brain is enclosed in the skull. There is no room for brain tissue to expand, and so the leaked blood can compress and kill important areas of the brain.  Hemorrhagic strokes tend to be more serious than ischemic strokes.
Horizontal definition, at right angles to the vertical; parallel to level ground. See more.
According to About.com, physics is the study of matter, energy and the way they interact. Physics is a natural science that also encompasses concepts like force and motion. The primary goal of physics is to understand how the universe behaves.