How does Oracle decides and returns the rows for a Select statement

Hi,

I have a very basic question on select query results.

When I run SELECT * FROM TABLE_NAME (no additional clause), how does Oracle decides which rows to present first and what mechanism does Oracle follows internally.

I checked the indexes and verified internal row_ids but I am unable to find a proper understanding.

I understand how it parses the SQL and the priorities of ORDER BY, GROUP BY etc. My question is related to the exact query "SELECT * FROM TABLE_NAME".

Please help me understand.

Thanks !