Final answer:
Between three and four minutes after the Big Bang, the universe resembled a primordial soup of particles. It was at this point that hadrons, such as protons and neutrons, began to form, and as the universe cooled, the fundamental forces differentiated and nucleosynthesis commenced.
Step-by-step explanation:
Between three and four minutes after the Big Bang, the entire universe was acting like a primordial soup of particles. During this time, known as the Hadron Epoch, the universe cooled enough to allow quarks to combine and form hadrons, including protons and neutrons. As the universe continued to expand and cool, it reached a state where the fundamental forces such as gravitational, electromagnetic, strong nuclear, and weak nuclear forces began to take on their distinct characteristics, ultimately leading to the formation of simple atomic nuclei in a process called nucleosynthesis.
Using particle accelerators, scientists today attempt to recreate the conditions of the early universe right after the Big Bang to better understand this critical period of cosmic history. These experiments help us to work backwards in understanding the evolution of the universe from its initial state of extreme density and temperature.