Assessment and Qualifications Alliance (AQA) GCSE Biology Paper 2 Practice Exam

When the concentration of a reactant is increased, the system responds by shifting the equilibrium position to counteract the change, according to Le Chatelier's principle. This principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust itself to partially counteract the change and restore a new equilibrium.

Increasing the concentration of a reactant means there are more reactant molecules available to engage in the reaction. As a result, the forward reaction that forms products will be favored, leading to an increase in the formation of products. This process continues until a new equilibrium is established, where the rates of the forward and reverse reactions are balanced once again but with increased amounts of products compared to the initial state.

Therefore, the correct answer reflects how the system attempts to restore equilibrium by producing more products in response to the increased concentration of that reactant.