a scientist randomly divided a group of 100 lab rats into tow groups of 50. One group was fed regular rat chow while the other was fed the same...

a scientist randomly divided a group of 100 lab rats into tow groups of 50. One group was fed regular rat chow while the other was fed the same amount of rat chow with added ddt. Both groups were housed in the same room with the same environmental conditions. At the end of the experiment, rats were weighed and the mean difference calculated. What variable(s) was/ were manipulated by the scientist? a)DDT. b)temperature c)weight difference d) both ddt and weight differences e)both temperature and weight differences