Answer:
are you talking about elements in periodic table...?
Answer:
At length is more precise, at some length is defining a length that is unknown.
Explanation:
It was at length with the other car.
At some length, we will stop.
I would say it is too wordy. Try breaking it into 2 sentences or combining them better.
Primary Source because the primary come from the person who actually live through what they wrote.
And secondary comes from the primary source but they might change stuff so that’s why it is not reliable.
