What is the rate of energy loss at different trophic levels in an energy pyramid (in $\%$)?

What do ecologists call the transfer of energy that begins with the sun and passes from one organism to the next in a food chain?

Which of the following is the source of energy for an ecosystem?

Assertion $A$: The amount of free energy in a system gradually decreases.
Reason $R$: During any transformation of energy,some amount of energy is lost in the form of heat.
Which option is correct for Assertion $A$ and Reason $R$?

Energy transfer from one trophic level to another in a food chain is: (in $\%$)

Of the total incident solar radiation,the percentage of photosynthetically active radiation $(PAR)$ captured by the plants is