Ann has a cold. she is coughing up mucus (a respiratory secretion) from her lungs. joann is the in the chain of transmission. the mucus from her cough is the in the chain of transmissio

I don't fully understand your question but what i assume you are trying to ask is WHY her mucus is part of the chain of transmission.

JoAnn's mucus still contains active cultures of the cold virus that is affecting JoAnn. thus her mucus would be able to transmit the virus to others.

Answerbasal cell carcinoma;