Apical dominance is caused by

The number of radial nodes of $3s$ and $2p$ orbitals respectively are

The oxide of nitrogen formed by thermal decomposition of $NH_4NO_3$ is

Given below are $2$ statements:
Statement $I$: The number of species among $BF_4^-$, $SiF_4$, $XeF_4$ and $SF_4$, that have unequal $E-F$ bond lengths is $2$. Here, $E$ is the central atom.
Statement $II$: Among $O_2^-$, $O_2^{2-}$, $F_2$ and $O_2^+$, $O_2^-$ has the highest bond order.
In the light of the above statements, choose the correct answer from the options given below

If $\overrightarrow{a}, \overrightarrow{b}, \overrightarrow{c}$ are three vectors such that $\overrightarrow{a}=\overrightarrow{b}+\overrightarrow{c}$ and the angle between $\overrightarrow{b}$ and $\overrightarrow{c}$ is $\frac{\pi}{2}$,then:

The value of $\int_0^1 \tan ^{-1}\left(\frac{2 x-1}{1+x-x^2}\right) d x$ is