The example of the great barrier reef is used to illustrate
a-the insignificance of coral reefs
b-the lack of diversity in the ecosystem
c-the consequences of increasing acidity
d-the problems that too much algae can relate

japan is the correct anwser because i already took the test and i passed it

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).