Bloodconsistsofbloodcellsandbloodplasma,inwhichthebloodcellsaresuspended.Thebloodcellsareerythrocytes(redbloodcells),plateletsandleukocytes(whitebloodcells).Mostmammalianerythrocytesarebiconcavediskswithoutnuclei.Thebiconcaveshapeprovideserythrocyteswitha (共 1570 字) [阅读本文] >>