Ozone is effective against

The correct choice indicates that ozone is effective against a range of pathogens and contaminants, which includes amoebic cysts, bacteria, phenols, and viruses. Ozone is a powerful oxidizing agent and has strong disinfectant properties, making it suitable for a variety of applications in environmental health and water treatment.

When considering its effectiveness, ozone can disrupt cellular membranes and denature proteins, which is effective against various microorganisms, including bacteria and viruses. It is also known to break down organic compounds like phenols, which are often found in wastewater and can pose health risks.

Moreover, cysts from protozoa, such as those from amoebae, are also susceptible to ozone. Ozone treatment can lead to the inactivation of these pathogens, making it a versatile tool in the disinfection arsenal.

Overall, the statement reflects ozone's broad-spectrum efficacy in addressing multiple categories of pathogens and contaminants, illustrating its utility in maintaining environmental health and safety.