Give scientific reasons: $Bt$ protein cannot kill $Bacillus$.

(N/A) $Bt$ protein does not kill $Bacillus$ because the $Bt$ toxin protein exists as an inactive protoxin within the bacterium. It only becomes active when ingested by an insect. The alkaline $pH$ of the insect's gut solubilizes the crystals,converting the inactive protoxin into an active toxin. Since $Bacillus$ lacks this specific alkaline environment and the necessary physiological conditions,the toxin remains inactive and harmless to the bacterium itself.