The law of diminishing marginal returns means that when one uses more and more of an input:

The law of diminishing marginal returns is an economic concept that describes a situation where, after a certain point, each additional unit of input results in less and less output. Here's how it works, step by step:

1. Initially, increasing the amount of a single input (like labor or capital), while keeping other inputs constant, leads to an increase in output (or production).

2. However, as you continue to increase that single input, there comes a point where each additional unit of input starts to produce less additional output than the previous unit did. This is the point of diminishing marginal returns.

3. If you continue to add more of that input, there will eventually come a point where adding more input actually decreases the total output. This is known as negative returns.

In summary, the law of diminishing marginal returns states that, in a production process with at least one fixed input, there is a point at which each additional unit of variable input yields smaller and smaller increases in output.