Every living animal uses some sort of specialized outer layer to protect itself and keep the inside of the body from leaking out, and also to prevent outside dangers from hurting the body. A breakdown in this outer layer triggers a wide range of reactions in an animal. When the outer layer is damaged, the animal must immediately turn on genes that help with repair of the outer layer and turn off genes of unwanted organisms. Many problems can happen when genes are not turned on and off properly. For example, if a repair gene is in the "on" state at the wrong time, then a large scar can form. Or, if the protection gene is in the "off" state at the wrong time, then an open sore can be an entrance for unwanted organisms and infections. Therefore, the balance between wound repair and protection is important to understand.
We performed our research using action/reaction questions, meaning we performed an action on the fruit flies (injuring the fruit fly cuticle, which is similar to the skin, with a small needle) and then observed the fruit flies to see their reaction to the injury.

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MPAA: PG
Go to source: https://kids.frontiersin.org/article/10.3389/frym.2016.00027