Root cap is absent in

If there is an error of $\pm 0.04 \text{ cm}$ in the measurement of the diameter of a sphere,then the approximate percentage error in its volume,when the radius is $10 \text{ cm}$,is

Which option is correct to match section $A$ with section $B$?

Section $A$	Section $B$
$(i)$ Nitrosomonas	$(a)$ $\text{Nitrite} \rightarrow \text{Nitrate}$
$(ii)$ Agrobacterium	$(b)$ $\text{Nitrogen fixing bacteria}$
$(iii)$ Rhizobium	$(c)$ $\text{NO}_3^- \rightarrow \text{N}_2$
$(iv)$ Nitrobacter	$(d)$ $\text{Ammonia} \rightarrow \text{Nitrite}$
	$(e)$ $\text{Denitrifying bacteria}$

Two long parallel wires are at a distance $2d$ apart. They carry steady equal currents flowing out of the plane of the paper as shown. The variation of the magnetic field $B$ along the line $XX'$ is given by

The smallest positive root of the equation $\tan x - x = 0$ lies in

The correct order of the $O-O$ bond length in $O_2, H_2O_2$,and $O_3$ is