The half-lives of isotopes are all measured in millions of years.
a. true
b. false

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

Describe the interaction that occurs between two objects with the same electrical charge.

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space