Which of the following refers to materials such as minerals and forests that occur naturally and can be used for economic gain?

The term that accurately refers to materials such as minerals and forests, which occur naturally in the environment and can be utilized for economic gain, is natural resources. These resources are fundamental to production processes and encompass a wide variety of items including water, air, and minerals, as well as trees and soil. The significance of natural resources lies in their availability and ability to contribute to the economy, forming the backbone of numerous industries.

Other options describe different categories of resources. Man-made resources refer to products that are created through human intervention or manufacturing processes, such as buildings and machinery. Capital resources are typically assets, like machinery or tools, that are used in the production of goods and services, which are also not naturally occurring. Economic resources is a broader term that includes all types of resources used in the production of goods and services, such as land, labor, and capital, but does not specifically focus on those that are naturally occurring. This clarity helps to distinguish between the categories and validates why natural resources is the most appropriate answer.