Question 1

Scientifically the 'Big Bang' offers the best explanation of the evidence of how the universe came into existence. The explanation is used as the basis for scientific research and works well with other scientific ideas. There are almost no scientists who do not accept at least the basis of the 'Big Bang' explanation. There are several pieces of evidence for the theory, including the fact that the universe is still expanding and, in 1965, the discovery of the microwave background radiation (the 'echo' of the explosion).

The 'life, animals, plants, water, humans etc.' of your question, and space itself, owe their existence to the conditions of the initial explosion which caused the universe. In 1859 Charles Darwin published his book On the Origin of Species which suggested how life evolved on earth.

Most religious groups seem to accept the part played by some form of evolution in the development of life on earth, but also believe that God used evolution as a method of creating life. Some religious groups do not accept this. You can read about different views of evolution on the Religious Tolerance.org website.