Your mouth, nose, throat, sinuses and lungs are lined with mucus membranes. These membranes contain mucus glands that produce - surprise - mucus. Mucus-producing membranes line specific passages in your body, like the respiratory and digestive tracts, for protection and support.
Infection of previous operation. The surgereon would need to go in and and remove the infection and possible a little more of the leg...
A,C,D,B that the order i would put them in