Researchers conducted an experiment to compare the starch content of tomato plants grown in sandy soil supplemented by one of three different nutrients, A, B, or C. The researchers selected 18 tomato plants and randomly assigned 6 plants to each nutrient group. After 6 weeks, the starch content of each plant was measured. What is the purpose of this experiment?
1) To determine which nutrient, A, B, or C, is most effective in increasing the starch content of tomato plants
2) To compare the growth rates of tomato plants grown in sandy soil with those grown in other types of soil
3) To investigate the effects of different nutrients on the overall health of tomato plants
4) To determine the optimal amount of nutrients to be used for tomato plant growth