Refer to the Figure Below

Multiple Choice

Refer to the figure below.A biochemist inoculated a test tube containing liquid medium with a few bacterial cells of a single species.A concentration gradient of oxygen was present in the tube, with very low levels of oxygen at the bottom of the tube and increasingly higher concentrations toward the top of the tube.The highest levels of oxygen were at the top of the liquid medium.Glucose was present in equal concentrations throughout the tube. The particular bacterial species used to inoculate the tube is able to grow either aerobically or anaerobically.Which tube would most likely represent the growth pattern of bacteria under these conditions?

A) Tube X, because these cells will not grow under conditions of low or no oxygen.
B) Tube Y, because these cells can grow under any oxygen concentrations.
C) Tube Z, because cells grow fastest when they harvest the greatest available energy from glucose.
D) Tube X, because cells cannot undergo fermentation in liquid culture.
E) Tube Y, because cells can undergo cellular respiration or fermentation equally well in liquid culture.