Read these sentences from the text. "Scientists repeated the experiment many times and could always tell which room had been occupied. They could measure bacterial 'clouds' in the room bacteria that had come off the person's body. Because every person's microbiome is unique, they could also identify different people from their bacterial clouds. Why might the author have placed the word "clouds" in quotation marks?
A to indicate that the word is being used in a different way than usual
B to quote the scientists who were doing the experiment
C to express surprise that clouds appeared inside a room
D to suggest that the measurements recorded by the scientists may not have been accurate​