Where is my blob stored?

Using oracle 11,

Although a lot was already written about blobs, there is something that is not still clear for me.

1. I was told that by default blobs stored in row if the are < 3900. Does it means that for a single table, some blobs will be stored in row and some others won’t?
2. Is there a way to check whether they are stored in row or not?
3. If I set ENABLE STORAGE IN ROW, does it means that whatever the size the blob has, it will be save within the same segment than the other data?

Oracle Doc says:

“When the size of the LOB stored in the given row is small,
approximately 4000 bytes or less, and you either explicitly specify
ENABLE STORAGE IN ROW or the LOB storage clause when you create the
table, or when you do not specify this parameter (which is the
default).”