You are presented with the question "What can make milk undrinkable?" and the following answer choices: 
- evaporation
 - Enzymes
 - boiling
 - glycogen
 - liquid
 - nutrients
 - bacteria
 - vaporization

Now knowing that bacteria cause food to spoil and milk was loaded with bacteria that quickly spoiled, making it undrinkable, choose the best answer.


 

       bacteria  