What type of reaction is characterized by the transfer of electrons from one species to another?

The correct answer involves understanding the nature of redox reactions, which are defined by the transfer of electrons between chemical species. In a redox reaction, one reactant is oxidized, meaning it loses electrons, while another reactant is reduced, meaning it gains electrons. This electron transfer is essential for many chemical processes, including combustion, respiration, and corrosion.

In contrasting types of reactions, acid-base reactions primarily involve the transfer of protons (H⁺ ions) rather than electrons. Precipitation reactions are characterized by the formation of an insoluble solid from two aqueous solutions, without any direct electron transfer. Complexation reactions involve the formation of a complex as a central metal ion binds to various ligands, typically through coordinate covalent bonds, rather than through the transfer of electrons.

Thus, the defining feature of a redox reaction—electron transfer—clearly supports its identification as the correct answer to the question.