Question

Productivity at the second trophic level is always:
A. greater than the productivity at the first trophic level always.
B. less than the productivity at the first trophic level
C. equal to the productivity at the first trophic level
D. extremely variable compared to the productivity at the first trophic level.

Answer 1

Hint: Productivity is the net rate of production of biomass per unit area per unit time. Productivity decreases with successive trophic levels. Like productivity at the second trophic level will always be less than that at the first one.

Complete step by step answer:
The term "productivity" in ecology refers to the rate of biomass production in an ecosystem, which is typically stated in terms of mass per volume (surface area) per unit of time, such as grams per square metre per day (gm²d^-1). The term "mass" can refer to either the mass of created carbon or to dry stuff. Ecosystems depend on the primary producers' (gross primary producers') productivity since these species provide energy to other living things.
Any ecosystem's ability to exist and operate depends on the availability of solar energy. Primary production is the amount of biomass or organic matter produced by plants during photosynthesis per unit area during a specific period of time. Either weight (gm^-2) or energy is used as the unit of measurement (kcal m^-2). The rate of biomass production is called productivity. The productivity of different ecosystems is measured in terms of (gm^-2 yr^-1) or (kcal m^-2 yr^-1). Net primary productivity (NPP) and gross primary productivity (GPP) are two ways to categorize it (NPP).
Productivity in the second trophic level is usually lower than at the first. This is due to the fact that only 10% of energy gets moved from one trophic level to another. Therefore, decreased production would be caused by less energy.
So, option (B) is correct.

Note:
According to Lindeman's (1942) formulation of the "10% law," only 10% of the energy present in a lower trophic level is captured by the next higher trophic level, with the remaining 90% being lost during transmission and respiration by the latter.