Which two factors are critical to the existence of the carbon dioxide (CO2 ) cycle on Earth?
A) life and atmospheric oxygen
B) life and active volcanism
C) plate tectonics and liquid water oceans
D) active volcanism and active tectonics
C
You might also like to view...
The darkness of clouds is due to
A) absorption. B) often being in the shadow of another cloud. C) both of these D) neither of these
A charged particle moving perpendicular to a magnetic field has a magnet force on it. But when an observer moves with the particle, so that the particle has a relative velocity of zero with respect to the observer, one would expect there would be no magnetic force. Yet there is still a force. If it is not a magnetic force, then what is the source of this force?
a. It is an electrical force. b. It is due to the ether. c. It is a gravitational force. d. It is something other than any of the above.
Atomic bomb tests demonstrated which aspect of star formation?
A) A shock wave surrounding and compressing a molecular cloud. B) The ignition of fusion that changes a protostar to a star. C) A protostar's movement on the Hayashi track. D) The fragmentation of a molecular cloud. E) A shock wave pushing a molecular cloud from one side.
Reacting an acid with a base gives water and
a. a carbonate. b. ammonia. c. carbon dioxide. d. a salt.