Why is the segment space occupied by inserting a record after the Oracle table is created 0.0625 MB?

The number and type of BUFFER headers in the buffer cache can be viewed through the preceding table, and you can see the SQL query results you have previously understood:

ZN @ PROD> select * from t8;

X Y
--------------------
1 2

ZN @ PROD> select segment_name, bytes/1024/1024 from user_segments where segment_name = 't8 ';
 
SEGMENT_NA BYTES/1024/1024
-------------------------
8. 0625

Why is the space occupied by segment 0.0625 M when a table is created and a record is inserted?

In fact, the object T8 generates eight different types of blocks (currently only five DATA blocks with class = 1 and one segment header with class = 4 are known, I don't know what BLOCK is for class = 8 & 9). If the size of each BLOCK is 8192 bytes, 8*8192/1024/1024 = 0.0625 M!