The image on the left shows human performance due to our muscles and the image on the right shows the internal combustion engine of a vehicle. 

Compare the two systems in terms of: i) what similar aspect justify them as machines, ii)  how does the stability/life-time of these engines differ, in terms of wear and tear, and from a fundamental perspective, why do you think this difference exists?

(Hint: In other words, one crucial point of similarity and difference between the two machine systems needs to be explained). Keep it short.