स्रोत स्तर पर अपशिष्ट पृथक्करण (waste segregation) का प्राथमिक उद्देश्य निम्नलिखित में से कौन सा 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)?