Which organisms are classified as pathogenic?

Which organisms are classified as pathogenic?

• A. Bacteria, viruses, and parasites
• B. Filtration systems and chemicals
• C. Non-beneficial insects and weeds
• D. Beneficial bacteria only

Answer: (A)

Pathogenic organisms are defined as those that can cause disease in a host. Bacteria, viruses, and parasites fall under this classification because they possess mechanisms to invade host organisms, circumvent immune responses, and cause harm. Bacteria can be harmful when they invade body tissues or produce toxins. Viruses hijack the host's cellular machinery to replicate, often leading to cell damage or death. Parasites, which can be protozoa or multicellular organisms like worms, can live off their host and cause various illnesses, affecting the host's health and functioning. The other options include filtration systems and chemicals, which are meant for water treatment and purification, and not living organisms. Non-beneficial insects and weeds might cause agricultural issues but do not cause diseases in the medical sense. Beneficial bacteria, while playing essential roles in ecosystems or human health, do not fall into the pathogenic category, as they typically promote health rather than cause disease. Thus, the organisms mentioned in the correct answer are specifically linked to disease-causing processes, distinguishing them from the other options provided.

Pathogenic organisms are defined as those that can cause disease in a host. Bacteria, viruses, and parasites fall under this classification because they possess mechanisms to invade host organisms, circumvent immune responses, and cause harm.

Bacteria can be harmful when they invade body tissues or produce toxins. Viruses hijack the host's cellular machinery to replicate, often leading to cell damage or death. Parasites, which can be protozoa or multicellular organisms like worms, can live off their host and cause various illnesses, affecting the host's health and functioning.

The other options include filtration systems and chemicals, which are meant for water treatment and purification, and not living organisms. Non-beneficial insects and weeds might cause agricultural issues but do not cause diseases in the medical sense. Beneficial bacteria, while playing essential roles in ecosystems or human health, do not fall into the pathogenic category, as they typically promote health rather than cause disease. Thus, the organisms mentioned in the correct answer are specifically linked to disease-causing processes, distinguishing them from the other options provided.