Farmers can use plant hormones to control the growth of plants. Give two uses of auxin.

Auxins are versatile plant hormones with several important commercial uses: - **Rooting Powders:** When taking cuttings from a plant, applying a powder containing auxins to the cut stem stimulates the growth of new roots, increasing the success rate of propagation. - **Selective Weedkillers:** Many broad-leaved plants (like dandelions) are very sensitive to high concentrations of auxin. When a synthetic auxin-based weedkiller is sprayed on a lawn, it causes uncontrolled, rapid growth in the broad-leaved weeds, which kills them. The narrow-leaved grass plants are much less affected, so the lawn remains unharmed. - **Tissue Culture:** Auxins are added to the growth medium in plant tissue culture to stimulate cell division and the formation of roots.