một thanh kim loại chưa bị nhiễm điện được cọ xát và sau đó trở thành vật mang điện tích dương đó là do thanh kim loại đã

The relationship of both of them

Shy diving is the only sport which doesnot require a high level of physical fitness

Year  1936,  lehman predicted that the earths 'inner core' is solid. she observed that the seismic signals during her study were bent and did not pass through instead bouncing back. later it was confirmed that the earth's inner core was solid made up of nickel-iron and had a molten outer core.