why does Bt toxin not kill the Bacillus?

Bt toxin is

Why Bt toxin gene does not kill the Bacillus bacteria in which it is found ?

Bt' toxin is :

Crystals of Bt toxin produced by some bacteria do not kill the bacteria because

Bt cotton is not :

In case of Bt cotton how does the toxic insecticide protein produced by bacterium kill the insect pest but not the cell Bacillus thuringiensis where the toxic protein is generated?

The Bt toxin is not toxic to human beings because :

What does Bt.Stand for ?

Why does an object fall down ?