Final answer:
The marginal product is the extra output resulting from adding one more worker, given constant capital and technology. The explanation highlights that the second worker's marginal product is higher due to the efficiency gained from using a two-person saw.
Step-by-step explanation:
The key concept being examined here is the marginal product, which refers to the additional output produced when one more worker is added to the production process, assuming all workers are homogeneous in terms of background, experience, and skills. While the initial scenario provided does not give the specific numbers for the outputs produced by the first and second workers, it does explain that the marginal product of the first worker is four trees per day, and the marginal product of the second worker is six trees per day. This increase in marginal product can be attributed to the use of capital such as a two-person saw, which operates more efficiently with two workers rather than one. To determine a specific marginal product or marginal cost, we would need data on the total outputs or total costs associated with the addition of workers or the production of units.