The first reason given is that the temperature of Lily's fridge is set to a low temperature, which slows down the decay process. When fruits like apples and lemons are exposed to higher temperatures, enzymes responsible for the breakdown of the fruits' tissues become more active, leading to faster decay. However, when they are stored in a refrigerator at a lower temperature, the activity of these enzymes is reduced, slowing down the decay process. This is why the fruits in Lily's fridge still look fresh even though they were bought at the same time.
The second reason mentioned is that the fruits may not have reached their expiration dates yet. Fruits, like other perishable items, have a shelf life or an expiration date. This date indicates the recommended time until which the fruits can be consumed while still maintaining their quality and freshness. If the fruits in Lily's fridge have not yet reached their expiration dates, it is likely that they will still look fresh.
In summary, the two reasons suggested for the apples and lemons in Lily's fridge still looking fresh are the low temperature in the fridge slowing down decay, and the fruits not yet reaching their expiration dates.