Iodine-131 is a radioactive isotope with a half-life of 8 days. how many grams of a 64 g sample of iodine-131 will remain at the end of 24 days?

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?

In 2002, the rare earth elements mine in mountain pass, california was closed because

Which of the following natural processes is most likely to support the formation of an underwater sinkhole? a pollution buildup from deposited minerals b limestone cave collapsing due to changes in sea level c erosion of large amounts of sand moved by ocean waves d oxidation of rock formed by chemical weathering