Table 1.1 lists three of the gases present in the atmosphere. Table 1.1 | gas | percentage | | :------------- | :--------- | | oxygen | | | carbon dioxide | | | nitrogen | | Fig. 1.1 shows a diagram of food packaged in this way. [Figure 1.1] This method of food packaging slows down decomposition of the food.

1. (a)Complete Table 1.1 to state the percentage of each gas in the atmosphere.[3]
2. (b)(i)Suggest how the percentage of one gas named in Table 1.1 is changed when used to package food in this way.[1]
3. (b)(ii)Explain how this change will slow down decomposition of the food.[3]
4. (b)(iii)Suggest two advantages of slowing down decomposition of packaged food.[2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.