<span>The birth rate decreased, while the death rate increased.</span>
One type of density change is mass over volume.
Explanation:
Whereas primary tissues allow for vertical growth, secondary tissues allow for lateral growth: they allow stems and roots to become wider. In roots, the formation of both secondary meristems involves the pericycle.
An ionic bond results in an exchange or transfer of electrons between the 2 different types of atoms, most likely the metal atom and nonmetal one.
For example the compound NaF is held together by electrostatic forces of positive and negative charges due to the transfer of electrons from the sodium to fluoride atom.
