Comparing cooling temperature changes at different stages of the universe's life provides evidence of (1:the radiation generated by the Big Bang expansion, 2:the forces that produced the original singularity, or 3:the rate of the universe's initial expansion). Measuring the universe's ratio of hydrogen and helium provides evidence that these elements were (1:formed long after the universe had cooled, 2:formed from the universe's original particles, or 3:generated by the universe's ongoing expansion).

Answer 1

The cooling temperature changes at different stages of the universe's life provide evidence of (3: the rate of the universe's initial expansion). This cooling corresponds to the expansion of space over time as the universe evolved from a hot, dense state following the Big Bang.

Measuring the universe's ratio of hydrogen and helium provides evidence that these elements were (2: formed from the universe's original particles). This process, known as Big Bang nucleosynthesis, occurred in the first few minutes after the Big Bang when the universe was hot and dense enough for nuclear reactions to take place, leading to the formation of these light elements.