What two forces primarily influence capital stock?

The correct choice highlights the key components that determine the capital stock within an economy: investment and depreciation.

Investment refers to the addition of new capital assets, such as machinery, buildings, and technology, which are vital for enhancing productivity and increasing the economy's capacity for production. This process of accumulating capital stock is crucial for economic growth, as it enables businesses to improve operations and expand.

Depreciation, on the other hand, represents the reduction in value of capital assets over time due to wear and tear, obsolescence, or age. As capital goods depreciate, they have a shorter useful life, which can lead to a decrease in the overall capital stock if not compensated by new investments.

Together, these two forces drive the net change in capital stock: investment adds to it, while depreciation diminishes it. It's essential to understand that without sufficient investment to replace depreciating capital, the productive capacity of the economy may decline, showing the dynamic relationship between these two factors.

The other options do not accurately capture the primary influences on capital stock. For example, consumption and savings, while related to economic activity, do not directly account for the changes in capital stock as effectively as investment and depreciation do. Revenue and costs are more associated with