What was the “oxygen revolution,” which took place 2.3 billion years ago? ?

Which of the following best describes a historical interpretation? o a. an unfair prejudice held by earlier cultures b. a source created in the ancient past o c. a conflict between ancient civilizations o d. an explanation for why a past event happened

One day as your professor is driving to work, another driver runs through a red light and hits his car. the professor is shaken up but survives the accident. however, the next time he starts to enter the intersection,he becomes nervous and fearful. soon,he starts going to work via another route to avoid the intersection even though this route adds twenty minutes to his commute in each direction. according to the principles of classical conditioning, why does the professor become scared of the previously harmless intersection? what can he do about this, as going via other route is very time consuming? be specific. break down the situation into its parts and show how the principles of learning apply.

Which of the following european countries settled the first colonies in america