In a species of garden snail, the allele causing a banded shell (bb) is recessive to the allele for unbanded shell (bo). similarly, for shell color, yellow (cy) is recessive to brown (cbw). a banded, yellow snail is crossed with a homozygous brown, unbanded snail. the f1 are then crossed with banded, yellow snails (i. e. in a testcross). what will be the results of the testcross if the genes for color and bands are linked and 20 map units apart?