वैश्विक जलवायु परिवर्तन के लिए जिम्मेदार मुख्य ग्रीनहाउस गैस कौन सी 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)?