द्वितीयक समंक (Secondary data) को मुख्य रूप से किस स्रोत से प्राप्त डेटा के रूप में परिभाषित किया जाता 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?