Exercise 3: Find the mistakes and fix
1. D. natural → naturally
2. A. importance → important
3. D. scientifically → scientific
4. D. economy → economic
5. A. optimist → optimistic
6. A. Desertify → desertification
7. C. destructive → destruction
8. D. cultivating → cultivates
9. C. cooperative → cooperation
10. C. human → humantarian