Identify the possible link A in the following food chain Green plant → Insect → Frog → A → Eagle

Given below are two statements: Statement I: In ecosystem, there is unidirectional flow of energy of sun from producers to consumers. Statement II: Ecosystems are exempted from 2nd law of thermodynamics. In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements: Statement I : The primary source of energy in an ecosystem is solar energy. Statement II : The rate of production of organic matter during photosynthesis in an ecosystem is called net primary productivity (NPP). In the light of the above statements, choose the most appropriate answer from the options given below:

Which of the following is the unit of productivity of an Ecosystem?

In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is $100 x\left(\mathrm{kcal} \mathrm{m}^{-2}\right) \mathrm{yr}^{-1}$, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?

Consider the pyramid of energy of an ecosystem given below:  If $T_4$ is equivalent to 1000 J , what is the value at $T_1$ ?