Blood must pass through the ........ to reach the left side of the heart.

$A$ magnet freely suspended in a vibration magnetometer makes $40$ oscillations per minute at place $A$ and $20$ oscillations per minute at a place $B$. If the horizontal component of earth's magnetic field at $A$ is $36 \times 10^{-6} ~T$,then its value at $B$ is

$y=A e^x+B e^{2 x}+C e^{3 x}$ satisfies the differential equation

Which nitrogenous base is present in $RNA$ but not in $DNA$?

Which of the following is absent in prokaryotes?

Which of the following ions forms the most stable complex compound?