A Houseplant Placed in a Window Grows Toward the Source

Multiple Choice

A houseplant placed in a window grows toward the source of light because auxin ____.
 

A) becomes more concentrated on the illuminated side of the plant
B) becomes more concentrated in the roots of the plant
C) becomes more concentrated on the shady side of the plant
D) inhibits the growth of cells on the shady side, so the cells on the sunny side grow larger
E) inhibits the growth of cells on the shady side, so the cells on the sunny side grow faster