19) How does the ocean remove carbon dioxide from the atmosphere?
A) By creating calcium carbonate
B) By converting seawater to carbonate gas
C) By neutralizing the carbon dioxide with glacial ice
D) By converting it to a food source for marine animals like foraminifera
20) How do foraminifera remove carbon dioxide from the seawater?
A) By breathing it in and converting it to oxygen
B) By consuming it and creating carbonic acid
C) By consuming it to create calcium carbonate shells
D) By breathing it in to create carbonic acid
21) Scientific knowledge of many events of the Precambrian is limited because ________.
A) Metamorphism altered and deformed many rocks
B) Plate tectonics consumed many of the oldest tectonic plates
C) Many ancient rocks have been eroded
D) Any ancient rocks have been covered by a mantle of sediments
E) All of the above