This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Endotoxins differ from exotoxins in that endotoxins 
Select and explain. 
A. are proteins, B. are heat labile, C. are highly antigenic, D. activate complement by the alternate pathway
D: activate complement by the alternate pathway
Answer: D: activate complement by the alternate pathway 
Explanation: None