Do you mind me asking why you chose 1912 as a start date? It just seems so random to me as nothing of note really happened that year. I'd love to provide an answer at least from a military standpoint from where I can but it may help to know your reasoning. Further anything specific you may want to know about would help as all inventions from 1912-2014 that can be considered 'major' is, well, more than one, two, or even three posters could reasonably cover.

I am afraid this question is far too large and all encompassing to answer meaningfully. Hence I've removed it. If you have a more specific question, please by all means resubmit.

I would also like to point you towards our rules concerning homework, should they apply:

Our users aren't here to do your homework for you, but they might be willing to help. Remember: AskHistorians helps those who help themselves. Don't just give us your essay/assignment topic and ask us for ideas. Do some research of your own, then come to us with questions about what you've learned. This is explained further in this [META] thread.