Setting aside the notion of determining the number of individual animals on the planet for a moment, merely determining the number of species on the Earth is challenging. Science has only been able to offer estimates thus far, and totals vary greatly.
A. A. A. Multiple sclerosis, or MS, is a long-lasting disease that can affect your brain, spinal cord, and the optic nerves in your eyes. It can cause problems with vision, balance, muscle control, and other basic body functions. The effects are often different for everyone who has the disease.
Brain cells in the area die from lack of oxygen. In another type of stroke, called hemorrhagic. (hem-or-AJ-ic) stroke, the blood vessel isn't blocked; it bursts, and blood leaks into the brain, causing damage. Strokes are more common in older people.