Based on the information provided within the question it can be said that this best illustrates that the children had developed a theory of mind. This theory refers to an individuals ability to attribute their own emotions, desires, knowledge or beliefs to other individuals as well as themselves. Which in this scenario since the Five-year-old's had already experienced the surprise of finding the pencils inside the Band-Aid box then they knew how their friends were going to feel when they opened the Band-Aid-Box.
Cardiovascular disease would be the most likely as the oxygen taken in is polluted and enters the blood stream. Thus as it travels to the heart and throughout your body you risk disease.