To get your parents to agree, try and ask them why they don't want you to get one. You can also ask if you can take care of one of your friends guinea pigs for a week or so and show them how responsible you can be. Make sure you know everything you will need to to take care of one.
Its possible that your cat might not get enough attention once the new pet gets there, so take extra good care of him. Your parents are trying to keep you from just getting one and then not taking good care of it once the newness wares off. More.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.