निम्नलिखित में से कौन सा धात्विक तत्व मुख्य रूप से पृथ्वी के क्रोड (कोर) में पाया 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?