Which is NOT true of mature red blood cells?
a. they have a nucleus
b. they have a biconcave structure
c. they contain hemoglobin
d. they transport small amounts of carbon dioxide
Its B because every cell has a nucleus and red blood cells are actually rich with hemoglobin and they release the carbon dioxide picked up from body tissues and become saturated with oxygen. (im sorry if this is wrong but im 89% sure im right)
