Which statement best describes a covalent bond? a
A chemical bond in which no electrons are shared.
b
A chemical bond that involves sharing a pair of electrons between
atoms in a molecule.
с
A chemical bond in which four or more electrons are shared.
A chemical bond in which one atom loses an electron to form a
d positive ion and the other atom gains an electron to form a negative
ion.

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.