Consider the following scenario: According to Sustainable Enterprises, coffee grounds can greatly benefit plants. They allow for a slow release of nitrogen and they can also increase nitrogen balance. Nitrogen helps plants use carbohydrates to gain energy. Nitrogen controls how plants take their form and how they function inside, and nitrogen helps plants make proteins that help them grow strong and healthy. Coffee grounds have been shown to increase the growth of plants because they have been said to release important nutrients used by the plants. According to Grow Joe, coffee grounds also release magnesium and zinc, micronutrients and amino acids. Without enough magnesium, plants may have brown/yellow older leaves. The coffee grounds can also feed earthworms; they loosen the soil; they retain water; and they release caffeine which repels slugs. Based on this information, students hypothesized that adding coffee grounds to the soil would affect the growth of Brassica rapa plants as measured by their leaf mass (size of leaves grown). They tested this by adding different amounts of coffee grounds to pots of soil before transplanting Brassica rapa seedlings into the pots. These amounts included 0,