Feeling the tremors of an earthquake,a scared resident of the seventh floor of a multistoreyed building starts climbing down the stairs rapidly. Which hormone initiates this action?

In the following common emitter circuit,if $\beta = 100$,$V_{CE} = 7 \text{ V}$,$V_{BE} = 0 \text{ V}$ (negligible),and $R_C = 2 \text{ k}\Omega$,then find $I_B$ in $\text{mA}$.

If $y=\tan ^{-1}\left(\frac{\sqrt{1+a^2 x^2}-1}{a x}\right)$,then $\left(1+a^2 x^2\right) y^{\prime \prime}+2 a^2 x y^{\prime}$ is equal to

Which one of the following is not observed in biodiversity hotspots?

Plants follow ...$A$... pathways in response to environment or phases of life to form different kinds of structures. This ability is called ...$B$.... Complete the given statement with the correct combination of options.

What is the small,circular $DNA$ molecule present in a bacterial cell,in addition to the main genomic $DNA$,called?