Question regarding Connection Pool mode in Universe connection settings (UDT)?

Hi,

In the Connection settings of a Universe we have 3 connection modes

1. Disconnect after each transaction

2. Keep the connection active for (time is set in Pool timeout)

3. Keep the connection active for whole session (local mode)

I understand that connection is to the Database (or datasource)

now if I say Disconnect after each transaction, what should be considered as a transaction over here and how does it reconnect after disconnecting?

when the mode is set to Keep the connection active for (time is set in Pool timeout is 10 minutes) what happens during this mode. After 10 minutes how does it reconnect?

and when the mode is set to Keep the connection active for whole session (local mode), what should be considered as a session?

Thanks