Practice Problem - A Multi-Part Study Experiment 1: Studying the microbiome of the gut has shown a number of interesting features when used to group or compare populations, affecting things as widespread as autoimmune disorders, autism, and obesity. Early studies showed that there are a greater number of species in lean individuals and lesser diversity in obese individuals' gut microbial populations. Researchers wanted to see if this was a correlative or causative relationship. Mice were raised in germ-free environments and then two groups received bacterial transfers from either obese women or their lean twin sisters. The groups of mice were fed the same diet in the same amount, drank the same water, and lived in isolated cages from each other. The results of this experiment showed that the mice that received microbes from the obese twin became heavier and had more body fat than the mice that got their bacteria from a lean twin! Complete the following for this scenario: Hypothesis: Dependent Variable: Independent Variable: Standard Variables: