1. Phototropism: Growth towards a light source.
2. Gravitropism (or Geotropism): Growth in response to gravity. Roots grow downwards (positive gravitropism) while shoots grow upwards (negative gravitropism).
3. Thigmotropism: Growth in response to touch or contact. Think of vines wrapping around a trellis.
4. Hydrotropism: Growth in response to water. Roots grow towards sources of water.
5. Chemotropism: Growth in response to chemicals. Pollen tubes grow towards the ovule in response to chemicals released by the ovule.
These are all examples of how plants respond to stimuli in their environment to optimize their growth and survival.
