What proportion of the total solar radiation is received as $PAR$?

The individual transitional communities in ecological succession are termed as

Both hydrarch and xerarch successions lead to $...........$ conditions.

What is a biogeochemical cycle? What is the role of the reservoir in a biogeochemical cycle? Give an example of a sedimentary cycle with a reservoir located in the Earth's crust.

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 $R$.

Which ones are the reservoirs of sulphur and carbon cycles respectively?