पृथ्वी के वायुमंडल में मुख्य रूप से ऑक्सीजन के कौन से दो तात्त्विक रूप पाए जाते हैं?

Which movement aimed to promote Khadi, a hand-spun and handwoven cloth native to India?

Who were prominent leaders associated with the initial phase of the Telangana Rebellion (1946-1951) against the Nizam's rule and feudal landlords?

What was the immediate trigger for the Revolt of 1857?