The student conducted experiments on pieces of brownie in test tubes to identify nutrients. Iodine turned the test tube black, indicating the presence of starch. Rubbing brownie on filter paper left a clear spot, showing there is fat. Benedict's solution turned the test tube yellow, meaning glucose is present. Tests did not show protein. The document then describes the digestion process, where starch is broken down to glucose in the mouth and stomach, fat is broken down in the small intestine, and nutrients are absorbed in the ileum while waste moves to the colon and anus.