Activational effect is the correct answer.
Activational effect is an impermanent hormonal effect that leads to a change in physiological activity or behavior in both humans and adult animals. For instance, when testosterone levels rise in male songbirds they become more aggressive and tend to engage in courtship behavior. Also, a pregnant woman may get more emotional than usual due to an extra level of progesterone and estrogen during pregnancy.
Explanation:
1] ADAPTATION : WE HAVE BEEN ADAPTING A DOG AS A PET.
2] BIODIVERSITY : BIODIVERSITY IS THE VARIABILITY AMONG LIVING ORGANISMS FROM ALL SOURCES INCLUDING TERRESTRIAL, MARINE, AND OTHER AQUATIC ANIMALS
3] ISOLATION : THE PROCESS OR FACT OF ISOLATING OR BEING ISOLATED
4] VARIATION : DIFFERENCE BETWEEN ORGANISMS OR PLANTS
SO, THIS IS YOUR ANSWER
Two atoms of oxygen element are represented as "20". The two oxygen atoms are unreactive state and are unstable readily reacts and form molecules.
O₂ reprersents one molecule oxygen. When the two oxygen atoms reacts with each other forms one molecule of Oxygen. After the formation of Oxygen molecule, it (oxygen) has got stability.
For the environmental risk, it is much better to prevent pollution than to deal with it after it has already been made. When you deal with the pollution, it is hard to say that you can eliminate completely. So, prevention is the first strategy.