The correct option is 1 only
Explanation
The Big Bang Theory, the prevailing cosmological model for the origin of the universe, postulates that the universe began from a primordial state often described as a singularity or a "tiny ball."
- Statement 1 is Correct: The theory assumes that in the beginning, all matter and energy in the universe were concentrated in one place with an unimaginably small volume (atom-sized or smaller).
- Statement 2 is Incorrect: The singularity was characterized by infinite temperature, not absolute zero. The universe was incredibly hot at its inception and has been cooling down as it expands.
- Statement 3 is Incorrect: The "tiny ball" possessed infinite density, not low density. The expansion of the universe led to the distribution of matter and a subsequent decrease in density.
Key Takeaway: The initial singularity in the Big Bang Theory is defined by infinite density, infinite temperature, and infinitesimal volume.