The use of genetically altered livestock, such as cows, goats, pigs, and chickens, to produce medically useful products is referred to as
selective breeding
artificial selection
farming
pharming

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.