'विज्ञान अवलोकन से शुरू होता है और अपनी अंतिम वैधता के लिए अवलोकन पर ही वापस आना पड़ता है।' निम्नलिखित में से किसने इसे रेखांकित किया?

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?