$DNA$ fingerprinting method is very useful for:

Select the two correct statements out of the four $(i-iv)$ given below about the lac operon.
$i.$ Glucose or galactose may bind with the repressor and inactivate it.
$ii.$ In the absence of lactose,the repressor binds with the operator region.
$iii.$ The $z$-gene codes for permease.
$iv.$ This was elucidated by Francois Jacob and Jacques Monod.

The properties of $Li$ are similar to those of $Mg$. What is the reason for this?

$50 \Omega$ and $100 \Omega$ resistors are connected in series. This combination is connected to a battery of $2.4 \text{ V}$. When a voltmeter of $100 \Omega$ resistance is connected across the $100 \Omega$ resistor,the reading of the voltmeter will be .......... $\text{V}$.

During the electrolysis of cryolite,aluminium and fluorine are formed in ........ molar ratio :

$75 \ mL$ of $0.2 \ M \ HCl$ is mixed with $25 \ mL$ of $1 \ M \ HCl$. To this solution,$300 \ mL$ of distilled water is added. What is the $pH$ of the resultant solution?