$A$ bryophyte,which harbours a nitrogen-fixing blue-green alga in its thallus,is

$A$ body projected vertically upwards crosses a point twice in its journey at a height $h$ just after $t_1$ and $t_2$ seconds. Maximum height reached by the body is

Among the following,which is water insoluble?

Which of the following bonds is the strongest?

In the expansion of $(1+x)^n$,the coefficients of the $p^{th}$ and $(p+1)^{th}$ terms are respectively $p$ and $q$. Then $p+q$ is equal to:

In which of the following production processes is limestone $(CaCO_3)$ $NOT$ used?