The Great Oxygen Event marks the time, approximately 2.3 billion years ago, when ________.
a. there was a massive volcanic eruption that lead to a very rapid increase in oxygen levels on Earth
b. there was significant oxygen in the atmosphere
c. there was a cataclysmic weather event that absorbed most of the oxygen in the atmosphere and locked it into iron deposits in the oceans
b. there was significant oxygen in the atmosphere
You might also like to view...
The hypothesis known as the demographic transition states as countries become industrialized and economically developed, their ____.
A. populations grow exponentially B. populations grow linearly C. populations grow more slowly D. per capita income falls E. poverty rates increase
The above graph shows that the farther people have to travel, the less likely they are to do so. The inhibiting effect of distance is ascribed to
A) the friction of distance. B) the problem of space. C) time-space convergence. D) cognitive distance. E) irredentism.
Given the following components:(1) lions and zebras(2) carbon dioxide and oxygen(3) grass(5) decomposers(6) the sun(7) nutrients(8) soil, air, and waterWhich are needed to have a functioning ecosystem?
A. All of them. B. Only 2, 3, 7, and 8 C. Only 1, 3, 5, and 7. D. All but 2.
Downcycling a material can also be described as ____.
A. primary recycling B. binary recycling C. secondary recycling D. refusing E. reusing