What is the study of living organisms called?

$A$ cell is connected between the points $A$ and $C$ of a circular conductor $ABCD$ of centre $O$ with angle $AOC = 60^{\circ}$. If $B_1$ and $B_2$ are the magnitudes of the magnetic fields at $O$ due to the currents in $ABC$ and $ADC$ respectively,the ratio $\frac{B_1}{B_2}$ is

Which mineral element plays a crucial role in nitrogen metabolism?

Which of the following is a square planar complex ion?

Which of the following aqueous solutions will exhibit the highest boiling point?

$A$ minimum value of $\int_0^x t e^{t^2} d t$ is