Leukonychia (or leuconychia), also known as white nails or milk spots, is a medical term for white discoloration appearing on nails. It is derived from the Greek words leuko (white) and onux (nail). The most common cause is injury to the base of the nail (the matrix) where the nail is formed.
Extinction Events. 1  There were many small-scale, sporadic extinction events during the Cambrian Period. 2  A large-scale mass extinction event occurred approximately 500 million years ago. 3  Scientists believe was caused by a significant decrease in global temperature. A large-scale mass extinction event occurred approximately 500 million years ago. 2  Scientists believe was caused by a significant decrease in global temperature. 3  Decrease in global temperature created an ice age-further eliminated many of the oceanic species.
What is a possible cause of the extinction event called the Great Dying? A. a meteorite impact that killed the dinosaurs B. a great outpouring of lava at the end of the Paleozoic C. a sudden increase in the oxygen content of the atmosphere during the Precambrian D. a new kind of super predator that devoured nearly all of the life in the oceans