Fossil fuels are substances that can be burned to produce energy. The burning of fossil fuels releases certain gases into the air. These gases combine with other chemicals in the air to form substances called acids. When trees on the top of mountains are exposed to clouds that contain these acids, the acids remove substances from the trees that help the trees fight against harmful insects.

Atmosphere and Biosphere

Explanation:

I took the assignment

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]

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).