Fact 1: Pneumonia may be caused by an infection or injury of the lungs.

Fact 2: Streptococcal pneumonia is caused by the bacteria Streptococcus pneumoniae.

Given the two facts above, answer the question "What can make lungs more at risk for infection by streptococcus?" with the following options: 
- Allergies
 - bacteria
 - Pollution
 - injury
 - fungi
 - sweating
 - the skin
 - smoking


 

    injury     