Chlorine is used in the pool water to not only kill germs, but also to:

Chlorine is used in pool water primarily for its disinfecting properties, effectively killing bacteria, viruses, and other harmful microorganisms. In addition to this crucial role, chlorine also serves to oxidize organic matter. This includes contaminants such as leaves, dirt, and sweat, which can accumulate in the pool. When chlorine interacts with these substances, it breaks them down, making the water cleaner and clearer. This oxidation process is essential for maintaining good water quality and preventing potential issues such as algae growth or unpleasant odors.

Other options do not accurately reflect the roles that chlorine plays in pool maintenance. For example, while stabilization of pH is important for water balance, it requires the use of specific chemicals and buffers, rather than chlorine itself. Priming the filters and lowering water hardness are also unrelated processes that don't involve chlorine in their function. Understanding chlorine’s multifaceted role in pool maintenance, including its ability to oxidize organic matter, is key for effective pool management.