What is the nucleus of a bacterium known as?

$I$ carried $1000\,kg$ of watermelon in summer by train. In the beginning,the water content was $99\%$. By the time $I$ reached the destination,the water content had dropped to $98\%$. The reduction in the weight of the watermelon was $.......\,kg$.

Which of the following reactants can be reduced by $SO_2$?
$I$. $O_3 \to$ product
$II$. $Cr_2O_7^{2-} \xrightarrow{H^{+}} $ product
$III$. $MnO_4^- \xrightarrow{H^{+}} $ product
$IV$. $H_2S \longrightarrow $ product

If $Q$ denotes the set of all rational numbers and $f\left(\frac{p}{q}\right)=\sqrt{p^2-q^2}$ for any $\frac{p}{q} \in Q$,then observe the following statements.
$I$. $f\left(\frac{p}{q}\right)$ is real for each $\frac{p}{q} \in Q$
$II$. $f\left(\frac{p}{q}\right)$ is a complex number for each $\frac{p}{q} \in Q$.
Which of the following is correct?

The minimum value of $2x^2+x-1$ is:

$X$ - In deep-sea hydrothermal vents,the average temperature is between $25^{\circ}C$ to $30^{\circ}C$.
$Y$ - Reptiles and amphibians are eurythermal.