stefan vickers teen divides the test subjects into groups according to the subject's poly genic scores and then they observe how the group with the especially high schizophrenia scorns develops the researchers are a long way off from totally understanding the complex genetics of psychiatric diseases but they are making progress. hello out there in a moment we'll be taking a look at me well us but even as we're pretty impressive small but mighty well not all that small we can reach out like that 135 centimeters and why up to 36 kilos. plus our fur is unusually thick gives humans have up to $600.00 hairs per square centimeter of skin we have up to $23000.00 tall that right here. at our tafe other stuff of legends. we use them to build gigantic structures like this a dam 850 meters long so big it's visible from outer space no wonder you call us busy. we might be rodents but we're also ecosystem engineers geniuses though not all humans agree. most people tend to think of beavers as a nuisance as pasts but it turns out that beavers are very beneficial to the ecosystem. here in the easy rive