निम्नलिखित में से किसे जैविक खाद (organic manure) के बजाय विशेष रूप से एक जैविक एजेंट या सूक्ष्मजीव-आधारित 'जैव-उर्वरक' (Bio-fertilizer) के रूप में वर्गीकृत किया गया है?

The 'Drain of Wealth' theory was propounded by which Indian nationalist leader?

Which event is considered the turning point in Mahatma Gandhi's leadership in the Indian independence movement?

Which African leader is known for his non-violent opposition to colonial rule?