A sample of expired air is collected in a gas jar. Another gas jar contains normal atmospheric air.
A lighted candle is placed inside each gas jar as shown. The time taken for each flame to go out is measured. As the candles burn they use up the oxygen available in the jar.
The table shows the results of this experiment.
The candle flame in jar X goes out in 15 seconds, while the candle flame in jar Y goes out in 9 seconds.
What is an explanation of the difference between the results in jars X and Y?
Select one of the following: