Which term corresponds to 'Produce toxins causing illness in humans'?

• A. Helpful Bacteria
• B. Bacteria
• C. Harmful Bacteria
• D. Protozoa

Answer: (C)

Toxins produced by certain bacteria can cause illness in humans, so the correct term highlights those organisms that cause disease through toxin production. Some bacteria release toxins (exotoxins or endotoxins) that disrupt normal body functions and lead to symptoms, making them harmful. Simply saying “bacteria” is too broad because many bacteria are harmless or even beneficial to our health. “Helpful bacteria” describes those beneficial roles, not illness-causing toxins. Protozoa are a different group of microorganisms and, while some can cause disease, their illness is not defined by toxin production in the same way. Therefore, the label that best fits the idea of producing toxins that cause illness is harmful bacteria.