A cosmological theory holding that the universe originated approximately 20 billion years ago from the violent explosion of a very small agglomeration of matter of extremely high density and temperature.
A black hole is a region of space in which the gravitational field is so powerful that nothing, including light, can escape its pull. The black hole has a one-way surface, called an event horizon, into which objects can fall, but out of which nothing can come
Yes, fish essentially breathe water through their gills, but they don't use the water to make energy, but the oxygen that is dissolved in the water. In essence, fish are like us except they use a different mechanism to get their oxygen!
White sunlight is really a lot of different colors of light mixed together. Some colors of light travel through air and dust better than others. Red goes a long, long way. But blue light gets bounced around a lot. Our blue sky is blue light that has been bounced out of sunlight by gazillions of molecules of air.