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 thoroughbred racehorse has reached top speeds of 55mph, almost double that of Usain Boltâs 100m world record top speed. However, thoroughbredâs arenât just fast, theyâre also known for their stamina and can maintain a pace of 16 mph for 60 miles.Talk about the ultimate ultra marathoner.he fastest thoroughbred racehorse has reached top speeds of 55mph, almost double that of Usain Boltâs 100m world record top speed. However, thoroughbredâs arenât just fast, theyâre also known for their stamina and can maintain a pace of 16 mph for 60 miles. Talk about the ultimate ultra marathoner.