Which of the following is a function of the immune system?

The immune system plays a crucial role in protecting the body from various threats, including pathogens such as bacteria, viruses, and parasites, as well as identifying and eliminating abnormal cells, such as those that are cancerous. By distinguishing between normal and abnormal cells, the immune system orchestrates responses that target and destroy these irregularities, thereby maintaining cellular homeostasis and overall health.

In contrast, the other functions listed are performed by different systems in the body. Absorbing nutrients is primarily a function of the digestive system, which breaks down food and allows for nutrient uptake. Producing hormones is mainly the role of the endocrine system, where glands secrete hormones that regulate various body functions. Digesting food also falls under the purview of the digestive system, which processes ingested materials to extract essential nutrients for energy and growth.