Collectively, what did the work of Charles Darwin, Francis Darwin, and Frits Went demonstrate about phototropism in plants?

Question

Quizplus · Accepted Answer

Charles Darwin and his son Francis demonstrated that the tip of the plant is responsible for sensing light and producing a signal. Frits Went later identified this signal as a chemical (auxin) that causes cells to elongate, resulting in growth towards the light.

Collectively, What Did the Work of Charles Darwin, Francis Darwin