The natural reservoir of phosphorus is ...

Distinguish between primary succession and secondary succession based on the following examples:
$I-$ Abandoned farmland
$II-$ Burned or cut forests
$III-$ Newly cooled lava
$IV -$ Bare rock
$V -$ Flooded lands
$VI -$ Newly created pond or reservoir
Identify the correct grouping for primary succession and secondary succession respectively.

The primary producers of the deep-sea hydrothermal vent ecosystem are

What percentage of incident solar radiation is included in $PAR$ (Photosynthetically Active Radiation)?

Match the ecological terms given in Column $I$ with its correct explanation in Column $II$.

Column $I$ (Terms)	Column $II$ (Explanation)
$1$. Stratification	$a$. Horizontal distribution of different species
$2$. Zonation	$b$. Rate of generation of Biomass in an ecosystem
$3$. Productivity	$c$. Breakdown of detritus
$4$. Decomposition	$d$. Vertical distribution of different species

Choose the correct option.

Phosphorus is mostly found in rocks in combination with