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:

Statement I asserts that the primary source of energy in an ecosystem is solar energy. This is true for the vast majority of terrestrial and aquatic ecosystems because photosynthetic organisms (plants, algae, cyanobacteria) capture sunlight and convert it into chemical energy, which then fuels the rest of the food web. Only a few specialized ecosystems, such as deep‑sea hydrothermal vent communities, rely on chemical energy, but these are exceptions. Therefore, the statement that solar energy is the primary energy source is correct.

Statement II claims that the rate of production of organic matter during photosynthesis in an ecosystem is called net primary productivity (NPP). The correct definition of NPP is the amount of carbon fixed by photosynthesis (gross primary productivity) minus the carbon respired by the producers themselves. In other words, NPP represents the net amount of organic material available to heterotrophs after plant respiration is subtracted. It is not simply the rate of organic matter production during photosynthesis; that rate is called gross primary productivity (GPP). Because the statement equates NPP with the raw production rate of photosynthesis, it is inaccurate.

Consequently, Statement I is correct, while Statement II is incorrect. The most appropriate choice is therefore “Statement I is correct but statement II is incorrect.”