Final answer:
The law of diminishing marginal utility explains why each unit of consumption provides less utility than the one before it.
Step-by-step explanation:
The law of diminishing marginal utility explains that each additional unit of a good consumed provides less additional utility than the previous unit. This means that the satisfaction or usefulness derived from consuming each successive unit of a good decreases.
For example, let's say you are eating slices of pizza. The first slice may bring you a lot of enjoyment and satisfaction. However, as you continue to eat more slices, the enjoyment you get from each subsequent slice diminishes. The law of diminishing marginal utility helps explain why we don't keep consuming more and more of a good.