I've uninstalled Xcode and many apps were uninstalled too I've uninstalled Xcode 4 to reinstall it:

sudo /Developer/Library/uninstall-devtools --mode=all


...and now I don't have Terminal.app and the Activity Monitor.app and I don't know what else apps were uninstalled.

I'm running Lion 10.7.2. Is there a way to recover this apps?
Both of those tools should be in your /Applications/Utilities folder. They should not be removed when uninstalling Xcode using that tool. 

If they are no longer there, you can copy them from another machine running 10.7.2. I would make sure to pull them from another machine running the same version of the OS. This is only if you know you are missing a particular application. 

The better route, if these applications are truly missing, would be to reinstall the OS, since as noted in the comment below, there could be many other items missing as well. With Lion, there is a new recovery tool built in. Make sure you backup your data first though. 

To recover, just hold down Command + R when rebooting. More information is available on Apples website.