You must design a valid experiment to show that there are microorganisms in the air. what would be your dependent variable? (points : 2) sterilized broth growth of organisms in the broth exposure to microorganisms in the air you must design a valid experiment to show that there are microorganisms in the air. what would be your control group? (points : 2) open flask with unsterilized broth open flask with sterilized broth sealed flask with unsterilized broth sealed flask with sterilized broth