An exotoxin that has the ability to kill or damage host cells is referred to as a(n):

• A. hemolysin
• B. cytotoxin
• C. enterotoxin
• D. neurotoxin

Answer: (B)

Verified step by step guidance

1. Understand the definition of an exotoxin: exotoxins are toxic substances secreted by bacteria that can cause damage to the host by targeting specific cells or tissues.
2. Identify the types of exotoxins based on their target cells or effects: for example, hemolysins target red blood cells, enterotoxins affect the intestines, neurotoxins affect nerve cells, and cytotoxins damage or kill a variety of host cells.
3. Analyze the question which asks for an exotoxin that kills or damages host cells in general, not limited to a specific cell type like red blood cells or nerve cells.
4. Recall that a cytotoxin is an exotoxin that specifically kills or damages host cells broadly, making it the correct term for this description.
5. Conclude that among the options given, 'cytotoxin' best fits the definition of an exotoxin that kills or damages host cells.