What are the primary functions of the digestive system?

The primary functions of the digestive system include ingestion, digestion, absorption, and elimination. Ingestion refers to the intake of food and liquids into the body, which is the first step in the digestive process. Digestion involves the mechanical and chemical breakdown of food into smaller components that can be easily absorbed. Absorption is the process where the nutrients from the digested food are taken into the bloodstream and distributed throughout the body to be utilized for energy, growth, and cellular repair. Finally, elimination is the removal of indigestible substances and waste products from the body.

This choice captures the essential processes that the digestive system is designed to perform. Other options include terms that do not precisely align with the functions of the digestive system. For example, respiration is not a function of the digestive system but rather part of the respiratory system. Similarly, filtration and secretion may refer to processes involved in other systems like the urinary system, and synthesis is more relevant in contexts such as metabolism rather than digestion directly. Thus, the correct answer comprehensively outlines the core activities specific to the digestive system's role in maintaining the body's nutritional needs.