Answer: Keeping those genes locally in the mitochondria gives the cell a way to individually control mitochondria,” Johnston says, because pivotal proteins are created in the mitochondria themselves. ... Other structures in our cells could also benefit from this type of local control.
In the experiment, the independent variable is the drug amount. Experiment group is given certain amount of drug, control group is not given the drug. The dependent variable is the body fat. I think you means the control is the living environment including food and water.
This kind of evolution where both species are evolving in response to one another is called coevolution.
It os being absorbed by the sea make it a long term because its a long process