Plasma membrane of a living plant cell is a double lipid layer with floating protein molecules. It selectively regulates the passage of substances into the cell and out of the cell. It is also describe by the statement that the plasma membrane of a living plant cell is selectively permeable.
Complementary is described as: combining in such a way as to enhance or emphasize the qualities of each other or another. So I think fitting together is sillier in the way that complementary loosely means when two things together make something better and when two puzzle pieces fit together they compliment each other by fitting together and making the bigger picture, hope this helps!
I did this one at school and the answer was: produces water