For Blank 1, the correct word is "respire." The sentence would read: "One by one, the students in the classroom next to the science lab began to look up and respire deeply at first and then quickly cover their noses."
For Blank 2, the correct word is "permeate." The sentence would read: "...and the smell was beginning to permeate the other classrooms on the hall."
So, the completed sentences are:
- respire
- permeate