Which of the following produces the maximum amount of organic matter?

$A$ is required for higher primary productivity. $B$ have the lowest primary productivity as the soil is deficient in moisture.
Choose the correct option for $A$ and $B$.

Total energy fixed by an ecosystem is called

Match the following columns correctly.

Column-$I$	Column-$II$
$(a)$ Gross Primary Productivity	$(1)$ $NPP$
$(b)$ Net Primary Productivity	$(2)$ $SP$
$(c)$ Secondary Productivity	$(3)$ $GPP$

The total energy fixed by a gram plant ($Cicer$ $arietinum$) in an ecosystem on the whole is called

In the equation $GPP - R = NPP$ (where $GPP$ is Gross Primary Productivity and $NPP$ is Net Primary Productivity),$R$ represents: