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: Social & Preventive Medicine
Ability of an organism to induce clinically apparent illness is known as: 
Select and explain. 
A. Infectivity, B. Pathogenicity, C. Virulence, D. Viability
B: Pathogenicity
Answer: B: Pathogenicity 
Explanation: Infectivity: It is the ability of an infectious agent to invade and multiply in a host. Pathogenicity: It is the ability of an organism to induce clinically apparent illness. Virulence: It is the propoion of clinical cases resulting in severe clinical disease. Ref: Park, 21st Edition, Page 34.