Sorry for the late reply. I dont understand what you mean by cartoons. can you tell me what exam board and link me an example?
Is it a piece of evidence, maybe showing certaing leaders or historical figures. I just think its a case of reading what they want and then identifying the visual clues as to their significance to people at the time and building on that. A cartoonisy may include prarticualr things or traits and you cna write about it. Cant really explain more unless i saw an example.