Final answer:
Bt toxin is a natural insecticide produced by Bacillus thuringiensis (Bt) bacterium. It is safe for the environment and non-toxic to humans.
Step-by-step explanation:
Bt toxin is considered to be a natural insecticide. Bacillus thuringiensis (Bt) is a bacterium that produces protein crystals toxic to many insect species. These crystals have been cloned and introduced into plants, allowing them to produce their own toxin to fight against insects. Bt toxin is safe for the environment and non-toxic to humans, making it an approved natural insecticide.