In $Protista$ and $Monera$,the parent cell divides into two to give rise to new individuals.

The value of $\cos^{-1}\left(\cos\frac{5\pi}{3}\right) + \sin^{-1}\left(\cos\frac{5\pi}{3}\right)$ is

Match the taxonomic categories given in column $I$ with their feature given in column $II$.

Column $I$	Column $II$
$A$. Taxon	$I$. Basic unit of classification
$B$. Species	$II$. $A$ taxonomic group of any rank
$C$. Phylum	$III$. Division is the same category in case of plants
$D$. Genus	$IV$. Identified based on a number of similar characters
$E$. Order	$V$. Group of related species having more characters in common with other species

If the harmonic mean between the roots of $(5+\sqrt{2}) x^2-b x+(8+2 \sqrt{5})=0$ is $4$,then the value of $b$ is

The fossil bone has a ${}^{14}C:{}^{12}C$ ratio,which is $\left( \frac{1}{16} \right)$ of that in a living animal bone. If the half-life of ${}^{14}C$ is $5730 \text{ years}$,then the age of the fossil bone is ......... $\text{years}$.

$A$ man standing on a road has to hold his umbrella at $30^{\circ}$ with the vertical to keep the rain away. He throws the umbrella and starts running at $10 ~km/h$. He finds that raindrops are hitting his head vertically. The actual speed of raindrops is: