Which groups are organisms divided into based on their primary ecological role?

During ecological succession,the diversity of species,the number of organisms,and the biomass $............$.

Classify the following ecosystems into their appropriate groups:
$I-$ Forest,$II-$ Grassland,$III-$ Pond,$IV-$ Desert
$V-$ Lake,$VI-$ Wetland,$VII-$ River,$VIII-$ Estuary
Terrestrial Ecosystem $\quad$ Aquatic Ecosystem

The last stabilized community in a plant succession is known as:

Hydrarch succession refers to ..........

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.