The picture shows a flower experiencing phototropism, a type of growth movement.

Question

Which of the following best explains what is causing the response in the picture?

a
The plant is being stimulated by an external stimulus, the indoor air, and is responding by growing toward the preferred outdoor air.
b
The plant is being stimulated by an internal stimulus, a need for water, and is responding by its roots pushing out of the soil in search of water.
c
The plant is being stimulated by an internal stimulus, the need for growth, and is responding by trying to leaving its pot because of a lack of space.
d
The plant is being stimulated by an external stimulus, the light through the window, and is responding by growing toward that light.

Answer 1

d
The plant is being stimulated by an external stimulus, the light through the window, and is responding by growing toward that light.