there is a near infinite number of answers here-
Anthropology studies how our ancestors coped with changing climates, interrelations with other species their environment, religion, interpersonal disputes...the list is literally endless.
One good example you can find at http://www.sciencedaily.com/releases/2007/06/070621140809.htm
wherein they discuss why certain people are more suseptible to HIV
and http://www.sciencedaily.com/releases/2009/09/090927145354.htm
helps us to understand the source of the virus, while
http://eprints.ucl.ac.uk/127801/
seems to offer a cure for this current event.