In human nutrition, micronutrients are nutrients required in relatively small amounts. Which of the following are examples of micronutrients?

Introduction / Context:
This health and nutrition question tests your understanding of micronutrients. While macronutrients such as carbohydrates, proteins, and fats are needed in large amounts to provide energy and structural material, micronutrients are required in smaller amounts but are essential for normal growth, immunity, and metabolism. The question asks you to identify which listed nutrients qualify as micronutrients.

Given Data / Assumptions:

• The options mention Vitamin A, calcium, and iron, and a combined all of the above choice.
• Micronutrients are defined here as nutrients required in relatively small amounts compared with macronutrients.
• Basic knowledge of the roles of vitamins and minerals is assumed.

Concept / Approach:
Micronutrients include vitamins (such as Vitamin A, Vitamin C, and the B complex) and mineral elements (such as iron, iodine, zinc, and calcium) that are required by the body in small amounts compared with energy providing nutrients. Vitamin A is a classic micronutrient; it is a fat soluble vitamin needed in small amounts for vision, immune function, and healthy skin. Iron is a trace mineral needed in relatively small quantities for haemoglobin formation and oxygen transport; deficiency leads to anaemia. Calcium, although needed in larger daily amounts than some trace minerals, is still classified as an essential mineral nutrient and widely taught together with other micronutrients in many exam oriented textbooks because it does not provide energy and is required in amounts much smaller than macronutrients like carbohydrates or fats. Therefore, all three listed substances can be considered micronutrients in the context of school level nutrition, making the all of the above option correct.

Step-by-Step Solution:

Verification / Alternative check:
Nutrition and health education materials often divide nutrients into macronutrients (carbohydrates, proteins, fats) and micronutrients (vitamins and minerals). Within micronutrients, they list Vitamin A, iron, and calcium as key examples, especially when discussing deficiency diseases such as night blindness (Vitamin A deficiency), anaemia (iron deficiency), and rickets or osteoporosis (calcium and Vitamin D related issues). School textbooks and public health campaigns frequently highlight Vitamin A, iron, and calcium together as important micronutrients for children and pregnant women. This confirms that treating all three as micronutrients in the exam context is appropriate and supports option D as the correct answer.

Why Other Options Are Wrong:

Vitamin A only, a fat soluble vitamin needed in small quantities, is wrong because although Vitamin A is a micronutrient, iron and calcium are also micronutrient minerals, so restricting the answer to Vitamin A alone is incomplete.

Calcium only, a mineral required by the body, is incorrect because it ignores Vitamin A and iron, which are also micronutrients and frequently discussed in nutrition education.

Iron only, a trace mineral needed for haemoglobin formation, is also wrong because focusing on iron alone leaves out Vitamin A and calcium, both of which are classic micronutrient examples.

Common Pitfalls:
Students sometimes think that only vitamins are micronutrients and forget that minerals are also included, or they are confused because calcium is required in somewhat larger amounts than trace elements like iron and iodine. Another pitfall is to focus on just one familiar example rather than recognising the broader category. To avoid these mistakes, remember that micronutrients include both vitamins and mineral elements such as Vitamin A, calcium, and iron, and in this exam style question, all of the listed items belong to the micronutrient group.