During science class, students were given a beaker containing warm water. They added one package of dry baker's yeast and some sugar to the beaker and recorded their observations in the table above before adding sugar and then again 20 minutes after adding sugar. The bubbles could mean that the yeast are alive and respiring or they could simply indicate a typical chemical reaction. What do you think would be the NEXT STEP the students should take to determine if the yeast are really alive? A) The students could leave the beaker overnight to see if anything solid grows.

B) The students could could take a sample from the beaker and observe it under a microscope, looking for cells.

C) The students should repeat the experiment using a timer to see how long it took for the bubbles to stop forming.

D) The students should repeat the experiment, this time using plain warm water and no sugar.