According to the figure shown below, about how long ago did oxygen first appear in Earth's atmosphere? About how long ago did oxygen reach 50 percent of its current abundance in Earth's atmosphere? 
Definitions:
Emotional Intelligence
The ability to understand, use, and manage one's own emotions in positive ways to relieve stress, communicate effectively, empathize with others, overcome challenges, and defuse conflict.
Self-Management
The ability to regulate one's own emotions, thoughts, and behaviors effectively in different situations.
Behavioral Scientists
Researchers who study the actions and behaviors of humans or animals, often focusing on the psychological, cognitive, or social aspects.
Self-Concept
A person's perception or image of themselves, formed through experiences and reflections.
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