1. Diminishing returns occur when the marginal product of the variable input is negative. 2. When the marginal product of labor is increasing, this is called increasing marginal returns. 3. It can be considered to be equivalent to the marginal product of new capital. 4. Diminishing marginal returns means that the marginal product of the variable input is falling. 5. Modern economics theorises productivity in terms of the marginal product of the factors of production. 6. The marginal product line shifts upwards to the right, that is to "'N1 " '. 7. "Marginal products are being weeded out, " he said. 8. It can be roughly considered to be equivalent to the marginal product of new capital. 9. When the marginal product of labor becomes negative, it is known as negative marginal returns. 10. Therefore, marginal cost is simply the wage rate w divided by the marginal product of labor