whats the difference between OVA and the জীবন্ত aired?

Well, আপনি probably already know what the definition of an OVA is, but it can be multiple things:
- A side story of an anime
- A prequel অথবা sequel of an জীবন্ত
- A short story almost completely disconnected from the জীবন্ত itself
- Fanservice
- An জীবন্ত series that simply didn't air on television, but stands on its own

If I like an anime, I'll usually check out its OVA if it has one. I will warn আপনি though, if আপনি watch the OVA's for every জীবন্ত আপনি watch, আপনি will eventually encounter some major wastes of time. It all depends on the show, though.