Построить 5 видов вопросов к предложению (the polluted sea water can become clean again thanks to some organisms)

Сan the polluted sea water become clean again thanks to some organisms?

What can become clean again thanks to some organisms?

The polluted sea water can become clean again thanks to some organisms, can't it?

Can the polluted sea water become clean or dirty thanks to some organisms?

Who/What help to clean the polluted sea water?