What is the average of the PH values?

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

Which statement best summarizes the importance of ernest rutherford’s gold foil experiment? it proved that all of john dalton’s postulates were true. it verified j. j. thomson’s work on the atomic structure. it showed that an electron circles a nucleus in a fixed-energy orbit. it showed that a nucleus occupies a small part of the whole atom.

Which scientists contributed to the determination of how cfcs in clouds in the upper atmosphere could destroy ozone molecules