Which of the following statements about essential nutrients is true?

Essential nutrients are substances that an organism cannot synthesize on its own and therefore must obtain from its environment. This category includes both macronutrients and micronutrients. Macronutrients, such as carbohydrates, proteins, and lipids, are needed in larger amounts and play critical roles in providing energy and structural components. Micronutrients, which include vitamins and minerals, are required in smaller quantities but are equally crucial for various biochemical processes and overall health.

The acknowledgment of both macro and micronutrients as essential highlights the diversity of nutrient requirements, reflecting the complexity of biological systems. This understanding is fundamental in fields such as nutrition and healthcare, where the balance and availability of these nutrients can significantly impact health outcomes.

In contrast, the other statements overlook key aspects of essential nutrients. For instance, not all essential nutrients are produced by the organism itself, which is reflected in the need for external sources of vitamins and minerals. Additionally, essential nutrients are not optional; their absence can result in adverse health effects, indicating their critical role in an organism's survival. Furthermore, essential nutrients are indeed required for the synthesis and function of macro-molecules, which are vital for cellular structure and function.