Worldwide, too little iodine in the diet is the most common cause of hypothyroidism. In countries with enough iodine in the diet, the most common cause of hypothyroidism is the autoimmune condition Hashimoto's thyroiditis.
The pronghorn is the second fastest land mammal in the world, after the cheetah. It can attain speeds of over 53 miles (86 kilometers) per hour. Size relative to a 6-ft (2-m) man: Fleet-footed pronghorns are among the speediest animals in North America. They can run at more than 53 miles (86 kilometers) an hour, leaving pursuing coyotes and bobcats in the dust.
The fastest thoroughbreds average nearly 40mph! And an average thoroughbred runs about 36 mph. The world record for a Thoroughbred racehorse's average speed over a mile is 43 â¦ miles per hour...but their spurts of speed can be slightly faster.he average top speed of a Thoroughbred racing horse is 63 kph (39 mph). This average for quarter horses is much faster: about 81 kph (50 mph).