Juliet started working with a radioactive substance. In 1997, she started with 200 g. When she measured again in 2002, she had 100 g left. In 2007, she had 50 g. Which substance is she most likely measuring?

rubidium-91
iodine-131
cobalt-60
carbon-14

Gold is not now being extracted from seawater. why not? a. it would be too disruptive to marine life to develop any marine mineral resources b. there is no gold in seawater c. we don't know how to extract minerals from seawater d. it would be too costly and difficult to separate the small amount of gold from the very large amounts of halite and other minerals

In order from largest to smallest what are earths five main oceans

The french to push mexican leader benito juarez out of blank . a) the oil industry b) poverty c)power