Anthrax is a serious illness caused by the Bacillus anthracis bacteria. The Bacillus anthracis bacteria create a dangerous toxin composed of three protein parts. Each individual part of the toxin does not cause symptoms of disease. However, when the three parts are combined, the toxin causes disease. Scientists know that one part of the toxin allows attachment to the host cells while the other two parts cause disease. The anthrax toxin is an example of a ____ toxin.  

• A. A-B toxin.
• B. LPS toxin.
• C. Endotoxin.
• D. Adhesin toxin.

Answer: (A)

Verified step by step guidance

1. Understand the structure of the anthrax toxin: It is composed of three protein parts, each of which is non-toxic on its own.
2. Recognize that one part of the toxin facilitates attachment to host cells, while the other two parts are responsible for causing disease.
3. Identify the type of toxin based on its structure and function: A-B toxins are characterized by having two components, where 'A' is the active part and 'B' is the binding part.
4. Compare the characteristics of the anthrax toxin with the definitions of the given options: A-B toxin, LPS toxin, Endotoxin, and Adhesin toxin.
5. Conclude that the anthrax toxin fits the description of an A-B toxin, as it has distinct parts for binding and activity, which is a hallmark of A-B toxins.