The cell membrane forms a protective barrier between the external and internal environments. it is referred to as because it allows some substances to cross more easily than others and blocks other substances from crossing into the cell.

2. cheryl hears a new song on the radio every day during the week on her commute to work. surprisingly, when the song comes on at a party on saturday night, she knows most of the words without trying. describe the three ways that we use cognition to learn without reinforcement. which type of cognitive learning without reinforcement best explains how cheryl knew the song lyrics? explain your answer.