Nerve cells do not divide because they do not have:

Which one of the following types of organisms occupy more than one trophic level in a pond ecosystem?

Cyclic photophosphorylation results in the formation of:

Among the bromides $(I)-(III)$ given below,the order of reactivity in $S_N1$ reaction is:

Which has the maximum number of molecules among the following?

Two loops $P$ and $Q$ are made from a uniform wire. The radii of $P$ and $Q$ are $r_1$ and $r_2$ respectively,and their moments of inertia are $I_1$ and $I_2$ respectively. If $\frac{I_2}{I_1} = 4$,then $\frac{r_2}{r_1}$ equals: