The silicates which contain $Si_2O_7^{6-}$ units are called

$\int_0^{\frac{\pi}{4}} \frac{\cos ^2 x}{\cos ^2 x+4 \sin ^2 x} d x=$

The pole of the straight line $x+4y=4$ with respect to the ellipse $x^2+4y^2=4$ is

Ethanol,when reacted with $PCl_5$,gives $A$,$POCl_3$,and $HCl$. $A$ reacts with silver nitrite to form $B$ (major product) and $AgCl$. $A$ and $B$ are respectively:

The magnetic susceptibility of the material of a rod is $499$. Permeability of vacuum is $4 \pi \times 10^{-7} \ H/m$. Absolute permeability of the material of the rod in $H/m$ is:

$A:$ Hormones are non-nutrient chemicals.
$B:$ They act as intercellular messengers and are produced in large amounts.