Define positive geotropism and negative geotropism. Give one example of each.

Explanation

**Step-by-Step Solution:**

1. **Define Geotropism:**
- Geotropism is the directional growth of a plant in response to gravity. It is a phenomenon where plant parts grow either towards or away from the gravitational pull of the Earth.

2. **Define Positive Geotropism:**
- Positive geotropism refers to the growth of plant parts towards the gravitational pull. This means that certain parts of the plant, such as roots, grow downwards into the soil, which is in alignment with the direction of gravity.

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