What is the main function of the digestive system?

The primary function of the digestive system is to break down food into smaller, absorbable components so that the body can effectively utilize the nutrients contained in the food we eat. This complex process starts in the mouth, where food is mechanically broken down by chewing and chemically altered by saliva. As food travels down the esophagus to the stomach and then to the intestines, it is further broken down by enzymes and digestive acids.

In the intestines, nutrients such as carbohydrates, proteins, fats, vitamins, and minerals are absorbed into the bloodstream and distributed to cells throughout the body. This nutrient absorption is crucial for energy production, growth, cellular repair, and overall maintenance of bodily functions.

While the other choices mention important bodily functions — such as circulation, hormonal regulation, and immune defense — they do not pertain primarily to the role of the digestive system, which is specifically focused on nutrient breakdown and absorption.