What's this?
microscope
What's this?
bacteria
What's this?
infect
What's this?
influenza
What are these?
cells
What's this?
disease
What's this?
virus
What's this?
swallow
What's this?
Common Cold
What's this?
paralyzed
What's this?
mucus
What's this?
scrape
What's this?
immune