First stars made the smallest elements, from hydrogen up and progressively larger stars made progressively larger elements
The first generation stars were mostly very massive and exploded as supernova.
Supernovas. First generation stars only had Hydrogen to convert into Helium. There were no other elements until the first supernovas and second round of star making occurred.
The first neutron stars likely formed some time in the first 600 million years after the Big Bang when large stars of the first or second generation died.
All elements heavier than iron which are found on earth were created when these stars went exploded as novae.
A first generation solar system would have contained mostly hydrogen and very little if any of the heavier elements. Second generation solar systems, made from the exploded remnants of first generation stars, would have a higher proportion of heavy elements and thus have more rocky planets and stars that could use energy sources other than hydrogen fusion after their hydrogen was exhausted.
Who are the stars of the Internet Lead Generation?
Our Sun is a population I star, that does not mean it is first generation - that title is held by population III stars. Our Sun is a 3rd (maybe 4th) generation star. See related question.
Without heavy elements, the clouds could not reach as low a temperature as today and had to be more massive to collapse.
What happens to a stars nuclear energy generation change if the core decreases in temperature?
2nd generation, yes. first, no
The main difference between first generation and fifth generation computers is upgrades. Typically, first generation is more of a beta system and fifth has had many upgrades added to it to make it run faster and has a better performance.
No. Charles messier made the first catalogue of stars and skies. His first version published in 1774 and other in 1781