I.out [美 aʊt, 英 aʊt]副out often appears as the second element of certain verb structures in English (come out, keep out, knock out, etc). For translations, see the relevant verb entry (come, keep, knock, etc).
These cells internalize the iron-containing hemoglobin, degrade it, put the iron onto transferrin molecules, and then export the transferrin-iron complexes back out into the blood.
His desire to be liked often leads him to make unwise decisions or unfeasible promises without considering the consequences, only to back out when they result in an undesirable comeuppance.