One, two and four are limitations of psychological experiments.
Lol relatable but what do you need help with ? is this the whole question ?
Answer:
Desertification
Explanation:
Drought and leaching leave some parts of Africa without much water, which leads to some portions of the area to turn into a desert, which can prove disastrous for the plants and animals that now find themselves in a completely different habitat.
Self intrest and exchanging things for mutual benefit
