A microorganism described as extremely harmful to hosts is said to be what?

• A. Volume
• B. Virus
• C. Verbal
• D. Virulent

Answer: (D)

The main idea here is virulence—the capacity of a microorganism to cause disease and harm in a host. When a microbe has a high ability to cause severe illness, we describe it as virulent. This term captures how strongly the organism can invade tissues, produce toxins, and evade the host’s defenses. So describing a microorganism as extremely harmful fits the word virulent.

The other words don’t fit: volume is unrelated to disease-causing potential, ver b al isn’t a biomedical term for microbes, and a virus is a type of microorganism, not a descriptor for how harmful it is.