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.
Primary brain tumors start in brain tissue and tend to stay there. Secondary brain tumors are more common. These cancers start somewhere else in the body and travel to the brain. Lung, breast, kidney, colon, and skin cancers are among the most common cancers that can spread to the brain.