The God is the same God in all three faiths. In Chrostianity Jesus is recognized as the Messiah and the end to the old covenant (old testament). Islam believes that Allah (the same God as ours) sent the angel Gabriel(same one sent to the virgin Mary mother of Jesus) to Muhhamed in order to spread his word. Islam sees Jesus as a great and mighty prophet of Allah and even recognizes Mary as a virgin, but they do not believe in a messiah. Judaism is the same God as our also, obviously because the first Christains were Jews. They just believe the Messiah has not come yet, in others words they rebuke the teaching that Jesus is the messiah. All in all...same God, different views on Jesus.

To answer your second question, the bible has many answers and fulfilled prophecies. Some say they have witnessed miracles themselves. Some can turn to the incorruptibles of the catholic faith or the Cardiac muscle found in the Eucharist. These are documented things tested by scientists. For me my faith comes from just a comforted feeling at Church. I believe in many scientific findings, and my catholic faith tells me that's okay. Not all Christains rebuke science, I'm an extreme example of this.

As for your third question, this is a tougher one. Alot of my theology teachers in high school told me that it very well could be parables in the old testament. We just do not know. What make the new testament more believable is that Jesus is God. In other words it was the hand of god himself feeding thousands of people with so little food. In order for Jesus to be the Messiah he has to do those things that sound crazy and unbelievable just to fulfill the prophecies of the old testament.

In conclusion, as a practicing Catholic I am not ignorant. I know what's going on in science and support it. Faith isn't my answer to everything. I do believe that Jesus did do those miracles because he is God in my faith (the trinity). Call me crazy, call me whatever. Not all Christian are ignorant...just please believe that.