Compared with Earth, the Moon has a surface that is geologically less active. For example
A.
both the Moon and the Earth have continents that move around.
B.
the Moon has many active volcanoes, while the Earth has none.
C.
the Moon has no active volcanoes, while the Earth has many.
D.
the Moon has continents that move around, while the Earth does not.

Tooth enamel consists mainly of the mineral calcium hydroxyapatite, ca_10(po_4)_6(oh)_2. trace elements in teeth of archaeological specimens provide anthropologist with clues about diet and diseases of ancient people. students at hamline university measured strontium in enamel from extracted wisdom teeth by atomic absorption spectroscopy. solutions with a constant total volume of 10.0 ml contained 0.726 mg of dissolved tooth enamel plus variable concentrations of added sr. added sr find the concentration of sr in the 10 ml sample solution in parts per billion = ng/ml. find the concentration of sr in tooth enamel in parts per million = mu g/g.