Which system is responsible for breaking down food and absorbing nutrients?

The digestive system is specifically designed for the purpose of breaking down food and absorbing nutrients. This system includes several organs such as the mouth, stomach, intestines, and pancreas that work together to convert food into energy and essential nutrients that the body needs to function properly. The process begins in the mouth, where food is mechanically broken down and mixed with saliva, then continues through the esophagus into the stomach, where further chemical digestion occurs. Finally, the small intestine plays a critical role in nutrient absorption, allowing the body to take in vitamins, minerals, carbohydrates, proteins, and fats.

The other systems mentioned, such as the nervous system, cardiac system, and muscular system, have distinct roles that do not directly involve the breakdown of food and nutrient absorption. The nervous system is primarily responsible for processing sensory information and coordinating bodily functions. The cardiac system deals with the heart and blood vessels, focusing on circulating blood throughout the body. The muscular system is involved in movement and stability but does not participate in the digestion or absorption of food. Thus, the digestive system is the only option that directly correlates with the processes described in the question.