Nutrients are absorbed in the intestines primarily through the process of diffusion and active transport. Once food is digested in the small intestine, its constituent molecules, such as glucose and amino acids, pass through the intestinal walls into the bloodstream. The villi and microvilli, small projections lining the intestinal surface, increase the absorption area, allowing for efficient nutrient uptake. This process is crucial for providing the body with essential nutrients needed for growth, energy, and overall health.