Final answer:
Among the options listed, 'exploiting natural resources' is an example that does not represent a positive effect of imperialism as it often led to the benefit of the colonizer more than the local population and had long-term negative impacts on the colonized area.
Step-by-step explanation:
All of the following are examples of positive effects of imperialism EXCEPT exploiting natural resources. The other options such as building railroads, improving education and increasing literacy rates, and building cities, roads, bridges, and dams can be seen as development initiatives that have potential benefits to the subject populations. Although infrastructure development may improve the lives of the colonized to a certain degree, the primary motive for such development is often to facilitate the extraction and transportation of resources, benefiting the colonizers more than the local population. Indeed, many infrastructure projects were designed with the sole purpose of extracting resources more efficiently, such as railroads that connected mines or plantations directly to ports. In addition, imperialism often resulted in the exploitation of natural resources in such a way that had little to no regard for the long-term economic, environmental, or social health of the colonized area.