Mad cow disease is causd by what type of poorly understood microorganism?

Mad cow disease is scientifically known as bovine spongiform encephalopathy, or BSE for short. BSE is caused by a mis-folded protein in the brain and spinal cord of cattle, so it is actually none of the above (virus, bacteria or protist). Prions are a novel form of disease infection distinct from the traditional three infectious routes identified in the early 1900s

It is evolution, because we all have some of the same traits like eye color or shape or ears.