ABSTRACT A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals , plants , fungi , and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures, such as hair, scales, feathers , or exoskeletons . Some nutrients can be metabolically converted to smaller molecules in the process of releasing energy, such as for carbohydrates , lipids , pr...
