Sometimes, a person is born with one or more

extra chromosomes in each cell. This usually

results in abnormalities because the affected

person has

(1) a reduced number of genes in cell nuclei

(2) fewer cell mutations than a person with a

normal chromosome number

(3) more genes in each cell than a person with a

normal chromosome number

(4) less DNA in cell nuclei, but more proteins in

cell mitochondria