A student has four snails, four sprigs of Elodea, eight test tubes of brom thymol blue, and two rooms (light and dark). The student wants to know what gases are produced by the snails and Elodea in li

A student has four snails, four sprigs of Elodea, eight test tubes of brom thymol blue, and two rooms (light and dark). The student wants to know what gases are produced by the snails and Elodea in light and dark conditions. Assuming the student only has time for one experiment, what setup will yield the most complete data?