What is an advantage of using nuclear power? a.
Nuclear power is generated at a lower cost than traditional methods.
b.
Nuclear power produces less pollution than traditional methods.
c.
Nuclear power is more efficient than traditional methods.
d.
All of the above

allowed for the prediction of the properties of missing elements.

i believe your answer would be c.. : )

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).