Minerals cannot be formed
a. by evaporation
b. in various chemical reactions
c. during the crystallization of magma
d. when a solid substance melts to form magma

What is the approximate chemical composition of the solar nebula?

Ozone in the upper atmosphere has been depleted by a. sulfur dioxide. b. chlorofluorocarbons. c. carbon dioxide. d. oxygen.

Which events occurred during the space race? check all that apply. (a) nasa was established. (b) yuri gagarin orbited earth. (c) the soviet union launched salyut. (d) the united states launched skylab. (e) the united states launched explorer 1.