You don't list any choices, but colloquialisms are used in informal speech. Hope it helps.
I would say its c Superlative
It means most important. For example, a priority for you would be to get good grades. It's currently the most important thing for you right now.
- drawing on her love of running, she decided to organize a 5 k.
- run to raise money for families of patients at a local children's hospital.
to help raise money for families of patients at a local children's hospital.
Answer;
The Huronian Supergroup <span>is </span>particularly<span> exciting and </span>interesting<span> because, by chance, these </span>rocks<span> were laid down at a period when the atmosphere underwent a transition from containing no free oxygen to containing at least some free oxygen.”
</span> Explanation;
The Huronian
Supergroup, a massive
formation of rock laid down
gradually between about
2.5 billion and 2.2 billion
years ago, precisely the
period when oxygen
began to accumulate in the
atmosphere. The Huronian Supergroup is 10 or 11
kilometers (six or seven
miles) thick and extends well below ground