कौन सी गंभीर रूप से लुप्तप्राय प्रवासी पक्षी प्रजाति ऐतिहासिक रूप से केवलादेव घाना पक्षी अभयारण्य में सर्दियों के दौरान आती 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?