Answer:
1.Cosmic Background Radiation (CBR): The CBR is a leftover glow from the earliest moments of the universe. Scientists predicted that if the Big Bang theory was true, there would be a remnant of this radiation in the universe. In 1964, two physicists discovered the CBR, providing strong evidence for the Big Bang.
2.Expansion of the Universe: The universe is constantly expanding, and the stars within it are moving away from each other. This phenomenon is called "Hubble's Law" after the astronomer who discovered it. According to the Big Bang theory, the universe began as a single point and has been expanding ever since.
3.Redshift of Light: The redshift of light is the stretching of the wavelengths of light as it travels through the universe. Scientists have observed that the more distant an object is from Earth, the more its light has been redshifted. This phenomena is called the "Doppler Effect," named after the physicist Christian Doppler, who was the first to describe it. According to the Big Bang theory, this redshift is caused by the expansion of the universe