Which parameter is used to determine the growth of flat organs like leaves?

Explanation

To determine the growth of flat organs like leaves, the parameter used is the **surface area**. Here’s a step-by-step explanation:

1. **Understanding Leaf Growth**: Leaves are flat organs, and their growth can be quantified by measuring how much their size increases over time.

2. **Measurement of Growth**: The growth of leaves is typically measured in terms of their surface area. This is because the surface area reflects the actual size of the leaf, which is crucial for processes like photosynthesis.

3. **Example Calculation**: In the provided example, one leaf grew from 5 cm² to 10 cm², while another leaf grew from 50 cm² to 55 cm². Both leaves had an absolute increase of 5 cm², but their initial sizes were different.

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