Z. mobilisis great at ethanol fermentationpartly because it blocks other commonly used pathways for glucose metabolism. The absence of what specificenzyme prevents Z. mobilisfrom undergoing glycolysis. Why is the absence of this specific enzyme a good (evolutionary) choice for blocking glycolysis

In the given question, the enzyme phosphofructokinase is absent that inhibits Z.mobilis from going through the process of glycolysis. Z.mobolis uses the Entner-Doudoroff pathway in the non-existence of enzyme phosphofructokinase in place of the EMP pathway to metabolize glucose. In the process, the pyruvate forms from sugars with the help of the Entner-Doudoroff pathway.  

Further, the fermentation of pyruvate takes place, which gets converted to carbon dioxide and ethanol. Yeast possesses the tendency to transform glucose into ethanol, however, not into xylose, that is, the five-carbon sugar, which is generally witnessed in the biomass. On the other hand, Z.mobilis with the assistance of the Entner-Doudoroff pathway undergoes fermentation of sucrose, glucose, and fructose into pyruvate.  

the answer is d.) homologous; have mammary glands