In my opinion, the correct answer among the choices listed above is option C. The Big Bang Theory states that between 15 and 20 billion years ago, the universe began expanding out of an enormous explosion. However, the exact number is approximately 13.8 billion years ago.
Answer:
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to 9,500,000,000,000 kilometers
That is not middle school grade level.
