The following picture shows _____________ in plants.

The correct answer is: Geotropism

The correct option is b)geotropism.

• Gravitropism or geotropism is the coordinated process by which plants undergo differential growth in response to the gravity that pulls them.
• Roots show positive gravitropism and stems negative gravitropism. That is, roots grow in the direction of gravity (i.e. down) and stems grow in the opposite direction (i.e. up).
• This behavior is easily demonstrated in potted plants.  When laid on its side, the growing part of the stem begins to exhibit negative gravitropism and grows upward.