Passage Summary: If you dry a grape to make a raisin, you only lose water. Since water has no calories or iron, it's weird that raisins end up having more iron per calorie than the grapes they started as.

Reasoning: Nothing is added to grapes to make raisins, and only water (which has no calories or iron) is removed, yet the iron-to-calorie ratio increases.

Analysis: The paradox here lies in the math of the ratio: if the numerator (iron) and the denominator (calories) both stay the same when water is removed, the ratio should remain constant. To resolve this, we need a reason why either the iron count goes up or the calorie count goes down during the drying process. Since the stimulus mentions that sugar 'caramelizes' during the process, look for an answer that suggests this chemical change reduces the caloric content. If calories drop while iron stays the same, the iron-per-calorie value will naturally increase.