You cant when you delete them there lost forever. Unless your worlds backed up.
No, deleted worlds are unrecoverable.
No
There are no commands in minecraft PE as far as I know.
there are no mods in minecraft pe i hope there will be
Yes. It is possible to crouch in the minecraft pe.
Depending on what you mean by "lose" your world it could be corrupted or not installed properly and you might have just acedently deleted it but if you did any of those thing I am sorry to tell you but think you will not be able to get it back.
There are no mods for Minecraft PE But it would be cool
there is no jungle biome in minecraft PE
If you have already purchased Minecraft PE, then update the game.
Minecraft PE 0.8.0 does not have squids in it.
there are no rumors for minecraft pe version 4.1
To get carrots in Minecraft PE you need to get seeds. You get seeds from zombies.