Why do the spectral lines for a transition in another element not occur at the same wavelength as the hydrogen lines?

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).

it should be d) transitional fossils.

they show the gradualism of evolution throughout a period of time