Which organisms have the greatest resistance to chlorine?

Nematodes exhibit the greatest resistance to chlorine among the listed organisms due to their protective cuticle, which serves as a barrier against chemical agents. This cuticle is a tough, outer layer that helps them survive in hostile environments, including exposure to disinfectants like chlorine.

While bacteria, protozoa, and viruses can also exhibit varying degrees of resistance to chlorine, they do not typically match the resilience found in nematodes. For example, some protozoa, particularly cyst-forming species, demonstrate notable resistance as well, but the robust protective features of nematodes often surpass those capabilities. Viruses may be sensitive to chlorine depending on their structure, while most bacteria are generally susceptible to chlorine concentrations that are used in water treatment processes. Thus, in the context of chlorine resistance, nematodes are the most resilient organism among these options.