शून्य ईंधन खपत और उत्सर्जन के कारण निम्नलिखित में से किसे खाना पकाने का पर्यावरण-अनुकूल (Eco-friendly) तरीका माना जाता 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)?