What is the function of a terminator gene?

$Bacillus \text{ } thuringiensis$ forms protein crystals which contain insecticidal protein. This protein

Given below are two statements:
Statement $I$: $Bt$ toxins are insect group specific and coded by a gene $cry$ $IAc$.
Statement $II$: $Bt$ toxin exists as inactive protoxin in $B. \text{ thuringiensis}$. However, after ingestion by the insect, the inactive protoxin gets converted into active form due to alkaline $pH$ of the insect gut.
In the light of the above statements, choose the correct answer from the options given below:

What happens in the $RNAi$ ($RNA$ interference) process?

Which of the following statements is correct regarding $Bt$ toxin?

$A$ infects the roots of tobacco plants,which reduces the production of tobacco.