What happens to Gibbs free energy (ΔG) when a system reaches equilibrium?
Becomes zero correctly describes the effect or change asked about in this question. In Bioenergetics, understanding cause-and-effect relationships is essential for predicting biological outcomes. Becomes zero occurs because of specific molecular interactions, thermodynamic principles, or regulatory mechanisms that govern this biological process. The other options (Becomes more positive, Becomes more negative, and Becomes infinite) describe either opposite effects, effects that occur under different conditions, or changes associated with unrelated processes.
Ref: Campbell Biology, Urry et al., 12th Ed.