Safari and Itunes store Apps has disappeared

Hi,

I have an Iphone 3GS 16Go with IOS 6.1.2. version.

Safari and Itunes Store icon are no longer present which is quiet annoying.

Besides, I can no longer erase any apps. The cross on the upper side of apps no longer exist.

Can anyboby help me out ?

Thanks a lot.

Virginie.