This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Which of the following is not a cultural characteristic of B. anthracis? 
Select and explain. 
A. Medusa head appearance, B. String of pearl reaction, C. Inverted fir tree appearance, D. Bamboo stick appearance
D: Bamboo stick appearance
Answer: D: Bamboo stick appearance 
Explanation: Ans. D. Bamboo stick appearancea. "Medusa head" appearance of colonies on solid medium is seen under microscopeb. "Inverted fir tree" appearance in gelatin stab culture.c. "String of pearl" appearance in culture medium with penicillin.d. Bamboo stick appearance is seen on gram stain as the bacilli form long chains.