Define the topic in seo ? Is it part of the internet marketing ?

Search Engine Optimization.

what is google sandbox…?

Oh, come on guys - you can do better than this. All those basic “What is …?” questions you can answer for yourselves with a quick internet search - or try Wikipedia. Please don’t post that kind of thing in the forums.

If, after you’ve done some basic research of your own, you still have a specific question which hasn’t been answered, then by all means come back and ask here. Meanwhile, thread closed.