The last one 'ed' is a suffix. It's commonly found at the end of a base word to change the meaning of it.
I hope you find this helpful :)
B) asthma sufferers. since the article is addressed directly to those who suffer from asthma attacks, it talks to them and makes specific recommendations about what they suffer and how they can avoid attacks.
2) The MAIN purpose of this selection isA) to identify the triggers for asthma. The article lists those actions or everyday objects that can trigger an asthma attack.