If your floor really needs more than that, consider a low-cost alternative to refinishing: Apply a fresh topcoat of nonyellowing polyurethane, found in the flooring section of a home improvement store. Be sure to very lightly sand the floors with a pole sander and fine-grit sandpaper.
There are 440 different species of sharks in the world today classified into eight different orders described below with some examples of known sharks species for each group.
In 2004, there were 61 unprovoked shark attacks recorded worldwide (seven were fatal), up from 57 in 2003. Overall, this number has been growing for the past 100 years, and more people were attacked in the 1990s than in any other decade (and so far it seems that the current decade will break last decade's record).