Gravitropism is the directional growth of a plant in response to gravity. Which of the following best describes an example of a plant exhibiting gravitropism?
A.
The flowers of a plant change color from blue to pink as the pH of the soil changes.
B.
The tendrils of a plant curl tightly around a wooden stake, allowing the plant to climb upward.
C.
As the seed of a plant germinates, the roots of the plant grow downward and the stems grow upward.
D.
As the stem of a plant grows, it grows slightly to the right in order to have better access to sunlight.