The toxic $Cry$ protein is released by the spores of . . . . . . which kills the larvae of butterflies feeding on plants like $Brassica$.

In plant cells,mutation can be induced by which of the following?

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:

The $Bt$ (Bacillus thuringiensis) strain was developed as a ...........

The transgenic food crop which may help in solving the problem of night blindness in developing countries is . . . . . . .

$BT$ cotton is resistant to