1. What do you mean by Bt?

 Bacillus thuringiensis (Bt) is a species of bacteria that lives in soil. It makes proteins that are toxic to some insects when eaten, but not others. The proteins are not toxic to humans because, like all mammals, we cannot activate them. Bt is not toxic to non-target wildlife. However, one type of Bt (aizawi) can be toxic to honeybees. Bt is used as an insecticide, typically, for insect larvae. Remember, it has to be eaten to work.