Law of Diminishing Marginal Utility

Describe the relationship between total utility and marginal utility.
Explain if marginal utility can be negative.
Examine the diamond-water paradox. Why are diamonds more expensive than water?
Evaluate the law of diminishing marginal utility.
Identify some items, explaining your reasoning, that do not follow the law of diminishing marginal utility.
Evaluate how the law of diminishing marginal utility can explain the diamond-water paradox.