Vertebrates begin to appear during what era

What is the formula that this ionic compounds could form sr2+p3-o2-

What is a possible quantum number set for an electron in the 3s orbital of a magnesium atom

The density of the solid phase of a substance is 0.90 g/cm3 and the density of the liquid phase is 1.0 g/cm3. a large increase in pressure will a. lower the freezing point b. raise the freezing point c. lower the boiling point d. raise the triple point e. lower the triple point