increasing the slope of the hill spraying herbicides on the hill adding plants to the hill removing grass from the hill
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Many houses are built on the sides of hills. Which of these actions would best prevent houses from sliding down hills after heavy rainfalls?
Possibilities:
- increasing the slope of the hill
- spraying herbicides on the hill
- adding plants to the hill
- removing grass from the hill

adding plants to the hill