The components of a bioreactor are:
$I.$ An agitator system
$II.$ An oxygen delivery system
$III.$ Foam control system
$IV.$ Temperature control system
$V.$ $pH$ control system
$VI.$ Sampling ports to withdraw cultures periodically
Choose the correct option.

Select the option that represents the correct sequence of steps in $r-DNA$ technology.
$(1)$ Insertion of $r-DNA$ into the host
$(2)$ Isolation of $DNA$
$(3)$ Ligation of $DNA$ fragment into the vector
$(4)$ Culturing the host cells in a medium at a large scale and extraction of the desired product
$(5)$ Isolation of the desired $DNA$ fragment
$(6)$ Fragmentation of $DNA$ by restriction endonucleases

For selection of recombinants,insertional inactivation of antibiotic marker has been superceded by insertional inactivation of a marker gene coding for a chromogenic substrate. Give reasons.

$A$ simple stirred-tank bioreactor is shown below. Identify $A, B, C, D$,and $E$.

$RNA$ is removed by the treatment with

Given below are two statements:
Statement $I:$ The $\text{DNA}$ fragments extracted from gel electrophoresis can be used in the construction of recombinant $\text{DNA}$.
Statement $II:$ Smaller size $\text{DNA}$ fragments are observed near the anode while larger fragments are found near the wells in an agarose gel.
In the light of the above statements,choose the most appropriate answer from the options given below: