In 2-3 sentences, explain how crossing over and independent assortment in sex cells affect the appearance of the fully developed organism. Compare how asexual and sexual reproduction affect the genetic variation of a population.

the answer is d. none of the above

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).