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.
Purposely bred for speed, greyhounds have been clocked at speeds of up to 45 mph. Nevertheless, the website Vetstreet reports that veterinarian Dr. Christine Zink suggests that many other lightweight, fast breeds are nearly as fast as greyhounds are, and reach speeds between 35 and 40 mph.