In fact, research in animals suggests that those animals who obtain more deep sleep following experimental challenge by microbial infection have a better chance of survival. (healthysleep.med.harvard.edu)
Until now, studies on limb preference of animals have focused solely on forced experimental challenges. (sciencedaily.com)
Warming has been observed on a global scale and no alternative theory can stand experimental challenge, can fit the data. (universetoday.com)