Final answer:
The true statement about the function of trace minerals in the diet is that they are essential in small amounts for various physiological processes.
Step-by-step explanation:
The true statement regarding the function of trace minerals in the diet is D) They are essential in small amounts for various physiological processes. Trace minerals are needed in much smaller quantities, often less than 150 mg/day, but they play crucial roles in the body's functions. Unlike macrominerals like calcium and phosphorus, which are needed in larger amounts, trace minerals such as iron, zinc, and iodine are integral to various physiological processes, including the formation of hemoglobin, immune system function, and thyroid hormone production. Consuming a varied diet is key to obtaining these nutrients without needing supplements, which could lead to potentially toxic levels.