What are the functions of anti-freeze in the coolant system?

Anti-freeze in the coolant system has two main functions. First, it lowers the freezing point of the coolant, protecting the engine from damage caused by freezing temperatures. Second, anti-freeze contains additives that help prevent corrosion inside the cooling system, which helps prolong the life of engine components. Therefore, both answers you chose are correct. Anti-freeze does not cause corrosion; instead, it helps prevent it. Remember these two key roles for similar questions: freeze protection and corrosion prevention.