Which of the following is used in biotechnology?

Statement $I$: $\text{RNA}$ interference $\text{(RNAi)}$ takes place in all eukaryotic organisms as a method of cellular defense.
Statement $II$: $Bt$ toxin protein is converted into an active form of toxin due to the alkaline $pH$ of the gut of an insect.

Genetic engineering is associated with:

Match the following columns and select the correct option.

Column-$I$	Column-$II$
$(a)$ $Bt$ cotton	$(i)$ Gene therapy
$(b)$ Adenosine deaminase deficiency	$(ii)$ Cellular defence
$(c)$ $RNAi$	$(iii)$ Detection of $HIV$ infection
$(d)$ $PCR$	$(iv)$ Bacillus thuringiensis

In which method is breeding carried out between a male and a female of two different species?

Read the following four statements $(1-4)$ and identify the two statements that contain mistakes:
$1.$ The first transgenic buffalo,Rosie,produced milk which was human alpha-lactalbumin enriched.
$2.$ Restriction enzymes are used in the isolation of $DNA$ from other macromolecules.
$3.$ Downstream processing is one of the steps of $R-DNA$ technology.
$4.$ Disarmed pathogen vectors are also used in the transfer of $R-DNA$ into the host.
Which are the two statements having mistakes?