D. Brain eating zombies we see in movies an in video games are impossible, and I won't explain because the person right below me did a good job and I agree with him. However, there are already diseases that can cause aggression on an extreme scale, and people with these diseases attack other people, and it can be transmitted through bodily fluids or bitting, which they will do because of their aggression, not because they are hungry. Aliens C. Don't know. Too early in our intergalactic exploration to know. I am Christian so I do believe they don't exist. The chances however, are quite high. Theoretically, (under a scientific mindset, not my own opinion) is that if there was a Big Bang, then the possibilities of how vast the universe really is, and the chances that another planet happened to have early life land on their planet, and that planet had whatever that early life needed to live, which could be very different from us and our theoretical early life. It's possible, but the chances of it being within even 1,000,000,000 light years are next to none. We likely will never no before humanity does of from a plague, natural disaster, war on a massive scale, getting too close to the sun, green house effect, etc. etc. any questions?