A Houseplant Placed in a Window Grows Toward the Source

Question

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

Accepted Answer

Auxin becomes more concentrated on the shady side of the plant, causing the cells on that side to elongate more than those on the illuminated side, thus making the plant bend toward the light.