Scientists are trying to reduce the amounts of carbon dioxide and methane that enter the atmosphere. which statement explains what will most likely happen as a result of these efforts?

These efforts will decrease the amount of heat that the atmosphere traps.

b a mature ovary of a plant.

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).