Much like whole organisms, cells must perform functions to survive. Some cell functions include obtaining energy and bringing in nutrients and water. What other function must a cell perform to stay alive? move from one organism to another produce bacteria get rid of wastes change into other kinds of cells

it would lead to upper respiratory infections and pneumonia.

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).