The last stage of plant succession is

The total quantity of global carbon is distributed such that $1\%$ is carbon in the atmosphere and $71\%$ is carbon dissolved in the oceans.

What is the full form of $PAR$?

Out of the total cost of various ecosystem services, the soil formation accounts for $P$, while contributions of other services like recreation and nutrient cycling are less than $Q$ each. The value of climate regulation and habitat for wildlife is about $R$ each. Identify $P, Q,$ and $R$.

Gaseous type of nutrient cycles are .......

During ecological succession,how does the complexity of the ecosystem structure change?