Down syndrome is caused by

a. a missing chromosome.
b. two X chromosomes.
c. an extra 21st chromosome.
d. the presence of an X and a Y chromosome.

Answer: c. an extra chromosome.

Psychology

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When adolescents refer to "popular kids," they are referring to kids who:

A) are well liked by others. B) have a lot of friends. C) are socially dominant leaders. D) all of the above

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In adoption studies, if a behavior has genetic roots, adopted children should behave more like their biological parents than their adoptive parents

Indicate whether the statement is true or false

Psychology