What conditions were necessary for the first matter to form in the Universe?
Explain why

hydrogen and helium couldn't form until the universe had cooled enough to allow their nuclei to capture electrons, about 380,000 years after the Big Bang. Within about 3 minutes after the Big Bang, conditions cooled enough for these protons and neutrons to form hydrogen nuclei.

Explanation:

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom

it should be briana that has it to me