The solar tracking (moving in the sun's direction) of the sunflower is called ______.

Heliotropism

The correct answer is Option (3) – Heliotropism

The solar tracking (moving in the sun's direction) of the sunflower is called: Heliotropism

Explanation:

• Heliotropism is the phenomenon where plants, or parts of plants, follow the movement of the sun across the sky.
• In the case of sunflowers, young flower buds and developing sunflower heads exhibit heliotropic movement by tracking the sun from east to west during the day.
• This movement is achieved by growth on the side of the stem facing away from the sun, causing the sunflower head to reorient and face the sun.
• Heliotropism is a type of tropism, which refers to the growth or movement of an organism in response to a stimulus, such as light.