Understanding one’s own emotions and how they affect others, recognizing one’s strengths and limitations, and demonstrating self-confidence is an example of:

Self-awareness

Explanation:

According to my research on studies conducted by various psychologists, I can say that based on the information provided within the question this is an example of Self-awareness. This term refers to an individuals capacity for seeing inside one's self and recognizing yourself as an individual that is separate from your environment and other people, by recognizing your strengths and weaknesses. Like mentioned in the question.

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b) the planets year length would be longer

hope this !