* Geotropism is the growth response of a plant to gravity.

* Positive geotropism means the plant grows towards the force of gravity. This is what happens with roots, ensuring they anchor the plant in the soil and access water and nutrients.

* Negative geotropism means the plant grows away from the force of gravity. This is what happens with stems and leaves, allowing them to reach towards light.

Let me know if you'd like more detail on geotropism!