Final answer:
The process of building larger molecules from smaller ones is described by an 'anabolic reaction,' which is part of anabolism and involves energy consumption to synthesize complex chemicals required by the body.
Step-by-step explanation:
The term that most precisely describes the process of building larger molecules from smaller ones is b) anabolic reaction. An anabolic reaction, also known as a biosynthetic reaction, involves the synthesis of complex molecules in living organisms from simpler ones. This process is fundamental in metabolic pathways and forms part of anabolism, which requires energy to convert small molecules derived from food into the complex chemicals necessary for the body.
An example of an anabolic process is the linkage of nucleotides to form a molecule of mRNA, which is utilized in protein synthesis. In contrast to catabolic reactions that break down complex molecules into simpler ones and release energy, anabolic reactions build up complex molecules and consume energy.