The number of angular and radial nodes of $4d$ orbital respectively are

Which of the following organisms derives energy for $N_2$ fixation through photosynthesis?

From which of the following is quinine obtained?

Which statement is incorrect regarding predators?

$NaOH$ is prepared by which of the following methods?

Given the standard electrode potentials,
$K^{+} / K = -2.93 \ V$,$Ag^{+} / Ag = 0.80 \ V$
$Hg^{2+} / Hg = 0.79 \ V$
$Mg^{2+} / Mg = -2.37 \ V$,$Cr^{3+} / Cr = -0.74 \ V$
Arrange these metals in their increasing order of reducing power.