Astudent recieved a flu shot in the fall. during the flu season the student caught a cold. the most likely reason the vaccine he recieved did not prevent the cold was that

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.