4. The relationships a population has with others in its community are: a. Always harmful b. Always beneficial c. Neither harmful nor beneficial d. Sometimes harmful and sometimes beneficial

Sometimes harmful and sometimes beneficial

Explanation:

The relationship of people living in a particular society or community can neither be generalized as being beneficial, neither can it be generalized as being harmful.

Activities such as, planting of trees, cleaning sewage and refuse etc are beneficial to the community while activities such as cutting down of trees, burning of wood pose threats to the society.

Going by the above explanation, we cannot specifically say that the relationship is toxic or beneficial but instead, it is safe to say that it is sometimes beneficial and it is sometimes harmful.

fertile good for trade etc