What makes someone self-centered? and what makes someone depressed?

(i really need to know this, cause my adopted sister is self-centered)

What is meant by a symmetrical unimodal distribution? a. a distribution is the frequency at which a certain value of a variable is obtained during a study. a symmetric unimodal distribution is a distribution where there is one value with a larger frequency than any other and the pattern of frequencies on the left and right of this larger frequency are mirror images of each other. b. a distribution is a pattern of frequencies for the various values of a variable collected in a study. a symmetric unimodal distribution is a distribution where there is one value with a larger frequency than any other and the pattern of frequencies on the left and right of this larger frequency are mirror images of each other. c. a distribution is the frequency at which a certain value of a variable is obtained during a study. a symmetric unimodal distribution is a distribution where there is a uniform frequency, meaning the frequency of every value is same, and the pattern of frequencies on the left and right of this larger frequency are mirror images of each other.

Congress checks on the power of the presidency by overriding a presidential reversal or veto. debating the bill in both of the houses. making laws without presidential review. sending the bill back to several committees

According to the theory of mercantilism, a country is strengthen by