what is amethyst? bc i have an amethyst crystal, my aunt says it helps with bad dreams and stress but how does it help, i also have green quartz, clear quartz and rose quartz

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

Which numberline shows the solution to n -3

Amountain is larger than a hill, with steep sides true or false