**Question:** An average-sized hen egg would provide

A. Vitamin D
B. Cholesterol
C. Omega-3 fatty acids
D. Iron

**Core Concept:** Eggs, particularly from hens, are a rich source of various nutrients that play a crucial role in human health and wellbeing. They consist of several components, including vitamins, minerals, proteins, and lipids.

**Why the Correct Answer is Right:** The correct answer is D. Iron, as eggs contain a significant amount of iron, especially in the yolk. Iron is an essential mineral for the production of hemoglobin and myoglobin, playing a vital role in maintaining healthy blood cells and preventing anemia.

**Why Each Wrong Option is Incorrect:**

A. Vitamin D: While eggs do provide vitamin D, the correct answer, D, is iron, not vitamin D. Vitamin D is found in other foods like fish, dairy products, and fortified cereals.

B. Cholesterol: Eggs contain cholesterol, but the correct answer, D (iron), is not cholesterol. Cholesterol is primarily found in animal products, such as meat, dairy, and eggs.

C. Omega-3 fatty acids: Although eggs contain omega-3 fatty acids, the correct answer, D (iron), is not omega-3 fatty acids. Omega-3 fatty acids are predominantly found in fatty fish, flax seeds, and walnuts.

**Clinical Pearl:** Eggs can serve as a valuable source of essential nutrients in a balanced diet. However, it is crucial to consider the nutritional balance of the overall diet and consume eggs in moderation to prevent potential health risks, such as heart disease, due to their cholesterol content.

**Correct Answer:** D. Iron

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An average-sized hen egg contains around **15%** of the daily recommended intake of iron (20mg) in the yolk (15mg) and the white (2mg). Iron is an essential mineral for hemoglobin and myoglobin synthesis, blood formation, and oxygen transport in the body.