A material originally contained 300 kg of uranium-235. The material now contains 281 kg of lead-207. Assuming that all the lead-207 came from the uranium-235,
how old is the material?

i dont know it at allnow im just getting points at this pint

the cost of mining is extremely low compared to the money earned from mining, creating income to improve the environment.

glacial erosion, the picking up and movement of earth beneath a glacier, is also referred to as plucking. erosion and transportation of individual pieces of bedrock, especially large "joint block occur as a result of this glacial erosion. plucking is type of erosion in which rocks become frozen into the bottom and sides of the glacier.as the glacier moves downhill it 'plucks' the rocks frozen into the glacier from the ground.