The taxonomic unit $phylum$ in the classification of animals is equivalent to which hierarchical level in the classification of plants?

If the terminal speed of a sphere of gold (density $= 19.5 \,kg/m^3$) is $0.2 \,m/s$ in a viscous liquid (density $= 1.5 \,kg/m^3$),find the terminal speed of a sphere of silver (density $= 10.5 \,kg/m^3$) of the same size in the same liquid.

Which is the lightest gas?

If $\int \sin ^{-1}\left(\frac{2 x}{1+x^2}\right) d x=f(x)-\log \left(1+x^2\right)$ then $f(x)$ is equal to

$A$ pair of perpendicular straight lines passes through the origin and also through the point of intersection of the curve $x^2+y^2=4$ with $x+y=a$. The set containing the value of $a$ is

In which of the following arrangements is the order $NOT$ according to the property indicated against it?