Which system is involved in the ingestion, digestion, and absorption of food?

The digestive system is specifically designed to handle the processes of ingestion, digestion, and absorption of food. This system includes various organs such as the mouth, esophagus, stomach, small intestine, and large intestine, each playing a pivotal role in breaking down food into nutrients that can be absorbed into the bloodstream.

Ingestion begins in the mouth, where food is taken in and mechanically broken down by chewing. Saliva begins the chemical digestion process. As food travels down the esophagus to the stomach, more digestive enzymes and acids work to further break it down. In the small intestine, the majority of nutrients are absorbed into the bloodstream, while the large intestine focuses on absorbing water and forming waste for excretion.

The other systems mentioned have distinct functions unrelated to the actual processing of food. The respiratory system is responsible for gas exchange, bringing oxygen into the body and expelling carbon dioxide. The nervous system controls body functions and responses but does not directly handle food. The circulatory system transports nutrients and oxygen to cells throughout the body but does not play a direct role in the digestion process itself. Therefore, the digestive system is the best answer as it encompasses all stages of food processing, from intake to nutrient absorption.