निम्नलिखित में से किस गतिविधि ने ग्लोबल वार्मिंग में अधिकतम योगदान दिया 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)?