Secondary productivity is:

Rate of formation of new organic matter by consumers.

The correct answer is Option (3) → Rate of formation of new organic matter by consumers.

Primary productivity refers to the rate at which energy is captured and stored by producers (plants, algae) through photosynthesis. It primarily depends on plant species, environmental factors (like sunlight, temperature), and nutrient availability. Primary production refers to the amount of biomass or organic matter produced per unit area over a given time period by plants during photosynthesis.

Secondary productivity is defined as the rate at which new organic matter is formed by consumers in an ecosystem. It represents the energy flow and growth of heterotrophic organisms, including herbivores and decomposers, as they consume and process organic matter.