Dr. mahr is studying the heritability of shyness. because her research participants are adolescents from different socioeconomic groups across the county, the heritability of self-confidence will appear to be a. low b. variable c. high d. constant

Variable--as there are too many testing variables within the research. Though they are all the same age (relatively) the participants are from different regions therefore different cultures and potentially differing races and ethnicities. Additionally, differing socioeconomic statuses will reveal varying parental and cultural attitudes which could impact self-confidence. SES also in itself can impact self-confidence as money can provide a future where poverty may create limits especially for an adolescent looking toward college or work goals beyond secondary education. 

Who knows, do another question and send it to me