The appearance of free oxygen in Earth's atmosphere led to the "Great Oxidation Event". Where did all of this oxygen come from? o A. Volcanic eruptions which spewed gases from the Earth's interior.
O
B. Cyanobacteria, a mutated unicellular organism, began to release oxygen as it performed photosynthesis.
O
C. The reduction of carbon dioxide which caused the Earth to freeze from pole to pole.
O
D. Oxygen was released from meteors during the Late Heavy Bombardment about 3.8 billion years ago.

c

explanation:

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

regents of the university of california v. bakke, 438 u.s. 265 (1978), was a landmark decision by the supreme court of the united states. it upheld affirmative action, allowing race to be one of several factors in college admission policy.

the answer is c. altitude. hope this ! #brainiac