This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
Most dominant colonic bacteria is 
Select and explain. 
A. Escherichia coli, B. Bacteroides, C. Clostridium, D. Veilonella
B: Bacteroides
Answer: B: Bacteroides 
Explanation: Bacteroids are the normal inhabitants of the intestine, respiratory, female genital tract. the normal flora of adult colon contains 96 to99% of anaerobes and only 1 to 4% of aerobes. Anaerobes - Bacteroides species, bifidobacteria, anaerobic lactobacilli, anaerobic streptococci. Ref: Baveja textbook of microbiology; 4th edition.