For example, stars are surviving because of the conversion of hydrogen into helium. In other words, stars have major deposits of hydrogen and helium. Our body also has same elements. If all the matter and energy originated from a single source and if it is impossible to make new energy or matter, it means that whatever the elements present in our body was once belonged to a heavenly object which is responsible for the evolution of our universe.
As per the observations made by NASA, "the universe was created sometime between 10 billion and 20 billion years ago from a cosmic explosion that hurled matter and in all directions" (Origin of the Universe). All stars and planets originated from this big bang as per the common belief of scientific world which forced Carl Segan to make the comment that we also once the part of