The first terrestrial plants are .......

Which of the following carbides will give propyne on hydrolysis?

If $\tan ^{-1} a+\tan ^{-1} b+\tan ^{-1} c=\pi$,then which of the following statements is true?

Two different radioactive elements with half-lives $T_{1}$ and $T_{2}$ have undecayed atoms $N_{1}$ and $N_{2}$ respectively,present at a given instant. The ratio of their activities at this instant is

What is the $B-F$ bond order in $BF_3$?

The diagram of a logic circuit is given below. The output $F$ of the circuit is represented by