A truck driver is transporting a load of unripe bananas in an airtight vehicle and decides to stop and eat an apple after checking on his cargo. He opens the back of his truck and, while walking around the unripe bananas, he decides the apple is overripe and drops it in the truck. When the bananas are finally delivered days later, he is surprised to find that all of his bananas have ripened. Why

Exposure of the bananas to the apple (and its ethylene) instigated their ripening.

Explanation:

A truck driver is transporting a load of unripe bananas in an airtight vehicle and decides to stop and eat an apple after checking on his cargo. He opens the back of his truck and, while walking around the unripe bananas, he decides the apple is overripe and drops it in the truck. When the bananas are finally delivered days later, he is surprised to find that all of his bananas have ripened. This is because the EXPOSURE OF THE BANANAS TO THE APPLE (AND ITS ETHYLENE) INSTIGATED THEIR RIPENING

rain should be the answer.