Question

PLEASE HELP 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

Answer 1

You can carry out a test , 
1- take a sample of the air in a test tube 
2-add limewater to the test tube 
3- result : if it turns milky/cloudy it has microorganisms 
4- reason: because every microorganism respires , and so it produces Carbon dioxide . 
and limewater is the test to show the presence of Carbon dioxide .