A baby is born with phenotypic characteristics of Down’s syndrome ; a rounded face, small chin, almond shaped eyes, and shorter limbs. Evidence from which of these techniques would best confirm the child has an extra chromosome 21

shorter limbs would be the best characteristic to confirm

Explanation:

answer: land bridge theory. land bridge theory held that shifting portions of dry land explained the finding of identical species on different continents. plate tectonic theory eventually eliminated the land bridge theory.