उप-सतही द्रव जलाशयों (जैसे भूजल और हाइड्रोकार्बन जलाशयों) का उचित प्रबंधन क्यों महत्वपूर्ण है?

Prolonged exposure to extreme cold temperatures may result in tissue damage known as frostbite, which is categorized as a:

In the context of ecosystem energy dynamics, which of the following expressions correctly defines Net Primary Productivity (NPP)?