If $\sin ^{-1} x - \cos ^{-1} x = \frac{\pi}{6}$,then $x$ is equal to

The solution set contained in $R$ of the inequation $3^x+3^{1-x}-4 < 0$ is:

Which of the following bacteria is associated with bio-insecticides?

The geometry possessed by $[Ni(CO)_4]$ is

$A$ working transistor with its three legs marked $P, Q$ and $R$ is tested using a multimeter. No conduction is found between $P$ and $Q$. By connecting the common (negative) terminal of the multimeter to $R$ and the other (positive) terminal to $P$ or $Q$,some resistance is seen on the multimeter. Which of the following is true for the transistor?

The first life on Earth was .....