Question

A flask filled with water and organic molecules was left open to the air for an hour and then was tightly stoppered. After being allowed to sit for a week, the flask was reopened and checked for living organisms. Only anaerobic bacteria were found living in it. Which of the following can be assumed about the conditions within the flask during the week it sat tightly stoppered?

Answer 1

The correct answer is A: 

When the flask is filled with water, the air supposed to be in the flask will be chased, then there will be no air and by the way no oxygen (or very few).

Anaerobic bacteria live in mediums which are deoxygenated (or like it was the case with the flask (there was no air and there were enough organic molecules to grow).