Which of the following describes how Earth's atmosphere changed during Precambrian time? A. The amount of carbon dioxide increased.
B. Torrential rains never reached the surface until the Paleozoic era.
C. The amount of oxygen increased.
D. Precambrian oxygen was quickly used up by plants.

Which statement does lola need to correct, and why? a) statement 1 because spiral galaxies do not havearmsb) statement 2 because the bulges contain mostlyyoung red stars. c) statement 3 because the arms are made of mostlyyoung blue and blue-white stars. d) statement 4 because spirals galaxies contain littleto no dust.(c)