Describes three types of stimuli that cause plants to exhibit tropism.

The three stimuli that cause the plants to exhibit tropism are:

1. Touch: This stimulus triggers thigmotropism, which is the turning or bending of the plant and tendrils in response to the touch.

2. Light: This stimulus triggers phototropism. It is how the plant reacts toward the direction of the light source. In this case, the stem may bend in response to the direction of the light.

3. Gravity: This stimulus triggers phototropism gravitropism, which is responsible for the downward growth of roots into the soil.