A: Some physical properties change, but the substance keeps its identity.
All the radiation from stars is the result of nuclear fusion in their cores.
you will find your answer through this link
https://www.britannica.com/event/New-Deal
That is the Sigma Symbol. It’s the addition of a sequence of numbers; the result is the sum of the total. if numbers are added sequentially from left to right, any intermediate result is a partial sum, prefix sum, or running total of the summation