Principle #1 Genetic Variation: Their is two type of mouse their is a brown one and a grey one, also the brown one camouflages to its surrounding and the grey one does not camouflage.
Principle #2 Overproduction & the Struggle for Existence: The overproduction is that the brown rat are surviving more due to being able to camouflage. The struggle of survival is the grey rat because it is not able to camouflage and so they are easy to spot from their predictor.
Principle #3 Differential Survival & Reproduction: The rats with brown color hair will survive and be able to reproduce because it is able to camouflage to its surrounding.
Principle #4 Changes in Gene Pool: The ones that have brown color hair will have more population because it is able to camouflage to its surrounding.