For which of the following microorganisms is chlorine a good disinfectant?

Chlorine is widely recognized as an effective disinfectant for a variety of microorganisms, particularly bacteria and viruses. When chlorine is used in disinfection processes, it works by penetrating microbial cell walls and disrupting their metabolic functions, which leads to cell death.

Bacteria, including both Gram-positive and Gram-negative species, are readily inactivated by chlorine. Similarly, a broad range of viruses, particularly enveloped viruses, are susceptible to chlorine, making it a strong choice for disinfecting surfaces and water to eliminate potential viral pathogens.

However, when it comes to protozoan cysts like Cryptosporidium, chlorine is less effective. Cryptosporidium has a robust protective outer shell that makes it resistant to chlorine treatment, which is why other methods, such as filtration or UV light, are often recommended for managing this particular microorganism.

Thus, the correct response indicates that chlorine is a good disinfectant for bacteria and viruses but not for Cryptosporidium.