These statements are all referring to

Analyze why south america is a place of ethnic diversity.

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.

The principal effector function of igm is