What is the source of complementary $dsRNA$?

Vitamin $A$ deficiency-induced blindness in developing countries can be reduced by using:

$RNAi$ stands for .........

What is the function of a terminator gene?

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:

Even though the highest number of varieties of this rice are found in India,which variety of rice was patented by a $U.S.$ company?