Is the microbial community in the intestine a key to understanding obesity? To explore this question, scientists conducted another experiment.

The scientists hypothesized that the microbial community of obese mice is more efficient at extracting energy from food, thus providing more calories to the host, and that it promotes more fat deposition than does the microbial community of lean mice. They decided to test this hypothesis by transplanting microbes from an obese donor mouse into lean mice.

For this experiment, the scientists randomly divided lean germ-free mice into two groups. The experimental group received microbes from a genetically obese donor (the donor's obesity was due to genetic factors, not diet). The control group received microbes from a genetically lean donor. Both groups were fed the same low-fat, high-fiber diet. After two weeks, the scientists measured the increase in body fat in the mice. They also determined the amount of energy (in kcal/g) in the feces of both groups -- that is, the energy in the food molecules that was not extracted or absorbed by the mice.

What experimental results would support the scientists' hypothesis? Label the bars on the graphs to match the results predicted by the hypothesis.

What experimental results would support the scientists' hypothesis? Label the bars on the graphs to match the results predicted by the hypothesis.