HESI A2 Science Practice Test 2025 – Complete Exam Prep

The term that describes the process of changing substances into a different form that entered the body is known as assimilation. This process occurs after digestion, where the nutrients from consumed food are absorbed into the bloodstream and transformed into forms that can be used by the body’s cells for energy, growth, and repair. Assimilation ensures that the body can utilize these nutrients effectively.

Metabolism is a broader term that encompasses all the chemical reactions that occur within the body, including both the breakdown of substances (catabolism) and the building of new substances (anabolism), but it does not specifically refer to the conversion of ingested substances into usable forms. Digestion specifically refers to the mechanical and chemical processes that break down food into smaller components before they can be absorbed, whereas excretion involves the elimination of waste products from the body rather than the transformation of substances into a different form.