How were large amounts of oxygen first introduced into earth's atmosphere?
a. they were deposited by comets that collided with earth.
b. they were released from the earth by erupting geysers.
c. they were produced as a byproduct of photosynthesis.
d. they were produced through atmospheric precipitation.

Describe at least three examples of how people and wildlife have adapted to their environments in the middle east.

The african continent is home of the worlds largest desert and longest river . t or f

Short answer/constructed response: respond to the question in 3-5 complete sentences. give details or examples to support your answer. attempt to answer all parts of the question in paragraph form! using the source 1 map, pick two of the 1800's territorial acquisitions you believe were the most important in the development of the united states. provide at least two reasons per territory to explain why you think they were the most important.