भू-पर्पटी में प्राकृतिक रूप से पाए जाने वाले रासायनिक पदार्थ जिनमें धातुएं या उनके यौगिक होते हैं, क्या कहलाते हैं?

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?