Final answer:
Essential elements required in very small amounts for life are called micronutrients or trace elements, such as Fe, Cu, and Zn, and are involved in various biochemical processes.
Step-by-step explanation:
Elements that are necessary for life but are only required in very small quantities are known as micronutrients or trace elements. These are indispensable to various biochemical processes despite their presence in cells in lower amounts compared to macronutrients such as hydrogen (H), carbon (C), oxygen (O), nitrogen (N), phosphorous (P), and sulfur (S). Examples of micronutrients include iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), and molybdenum (Mo). These elements are crucial for the proper functioning of an organism's body and are often required in concentrations expressed in parts per million or parts per billion.