What is the major function of the valves found in human veins?

Which supports the idea that birds and butterflies both have wings but they do not have a common ancestor with wings? the wings are analogous structures that evolved differently and do not have a similar internal structure. the wings are homologous structures that evolved differently and do not have a similar internal structure. wings of birds are vestigial structures, but the wing structures of bats are not vestigial. wings of bats are vestigial structures, but the wing structures of birds are not vestigial.

This patient undergoes a gallbladder sonogram due to epigastric pain. the report indicates that the visualized portions of the liver are normal. no free fluid noted within morisons pouch. the gallbladder is identified and is empty no evidence of wall thickening or surrounding fluid is seen there is no ductal dilation. the common hepatic duct and common bile duct measure 0.4 and 0.8 cm respectively. the common bile ductmeasurement is at the upper limits of normal what cpt code in icd-10 cm code was used

Which is not a type of symmetry? a. asymmetryb. radial symmetryc. bilateral symmetryd. lateral symmetry