Cardiac muscles contract:

The following reaction is an example of a ....... reaction. $CH_2Br-CH_2Br + 2KOH(alc.) \xrightarrow{\Delta} CH \equiv CH + 2KBr + 2H_2O$

In $Fe(CO)_5$,the $Fe-C$ bond possesses

Let $PQ$ and $RS$ be tangents at the extremities of the diameter $PR$ of a circle of radius $r$. If $PS$ and $RQ$ intersect at a point $X$ on the circumference of the circle,then $2r$ equals

Three students $A, B$,and $C$ are given a mathematics problem. The probabilities of them solving the problem are $1/2, 1/3$,and $1/4$ respectively. What is the probability that the problem is solved?

The metal used for the de-bromination reaction of $1, 2-dibromoethane$ is: