Blood vessels with green colour

they are veins. becoz they carry deoxygenated blood, which red blood cells contain less oxygen, so their colour appear under our skin is like green in colour.

錯。
靜脈的顏色非當中血液的顏色。因為靜脈外圍由不少纖維組成，其厚度使其不透明。
靜脈的綠色是其外圍肌肉纖維的顏色，而非血液的顏色。