the disease-causing particles cells exposed to the disease toxins released by diseased cells disease-specific antibodies
I gave my students this multiple choice question: Scientists determined that specific agents produce specific diseases, and many are transmitted by sneezing. What must the droplets contain for a disease to be transmitted by sneezing?

Only one answer is correct among these 4 choices:
- the disease-causing particles
- cells exposed to the disease
- toxins released by diseased cells
- disease-specific antibodies

Could you tell me which one is correct?

the disease-causing particles