In a population of bison, the birth rate over one year is
fourteen. No bison immigrate into the population that
year. Twenty bison die during the harsh winter, and ten
more leave the population in search of more food. What
has occurred in this population over one year?
The size of the population has increased.
The size of the population has decreased.
The size of the population has remained the same.

not only is it colder, it also becomes darker, less salty, and more dense.

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).