The venous system of a frog differs from that of a mammal due to the presence of:

In the adjacent circuit,a voltmeter of internal resistance $R$,when connected across $B$ and $C$,reads $\frac{100}{3} \text{ V}$. Neglecting the internal resistance of the battery,the value of $R$ is

In how many ways can a team of $10$ players be selected from $22$ players,such that $6$ particular players are always included and $4$ particular players are always excluded?

Which vegetable was absent in India before the arrival of European explorers?

Which of the following metals releases hydrogen gas upon reaction with cold and dilute $HNO_3$?

$A$ closed hollow insulated cylinder is filled with gas at $0^oC$ and also contains an insulated piston of negligible weight and negligible thickness at the middle point. The gas on one side of the piston is heated to $100^oC$. If the piston moves $5\,cm$,the length of the hollow cylinder is ..... $cm$.