In which form can the productivity of ecosystems be compared?

In relation to Gross primary productivity and Net primary productivity of an ecosystem,which one of the following statements is correct?

The rate of formation of new organic matter by a rabbit in a grassland is called:

$A$: In secondary productivity,no new organic matter is formed.
$R$: It is only the utilisation of part of food manufactured by primary producers in the building of consumer biomass.

Which one of the following ecosystems is more productive in terms of carbon dioxide fixation?

The rate of formation of new organic matter by consumers is .........