Astudent 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?

the last one: artificial selection/genetic engineering

plant breeding is modifying the genetic composition of the plant - but this isn't cloning (which is specifically introducing a gene into a genome). but you are artificially selecting for the phenotype that you want.

the second one is literally genetic engineering - the gene would have been cloned first and then inserted or genetically engineered into the new plant cell (the cotton).