Fact 1: Amold spore has a negative impact on the respiratory system.

Fact 2: Molds and spores thrive in water-damaged furniture and carpets.

Given the two facts above, answer the question "what has a negative impact on the respiratory system?" with the following options: 
- harmful substances
 - water-damaged carpets
 - a pathogens
 - lungs
 - density
 - oxygen
 - Something that causes allergies
 - some viruses


 

  water-damaged carpets       