During experiment yeast fermentation ，how is the anerobic condition maintained to ensure that the fermentation process is completed？​

By covering the solution.

Explanation:

The anaerobic condition is maintained to ensure that the fermentation process is completed by covering the solution so that no oxygen enters the solution. Anaerobic conditions are necessary for the fermentation process because the anaerobic conditions allow the production of lactic acid, ethanol and carbondioxide gas from pyruvate. Without anaerobic condition, the fermentation process does not occur so that's why we can say that anaerobic conditions should be maintained for the fermentation process.

answer; the above statement is (true);

substitution is the answer in this case