List a few structural modifications which occur during cell differentiation.

Explanation

### Step-by-Step Solution:

1. **Understanding Cell Differentiation**:
- Cell differentiation is a crucial process in the growth and development of plants. It involves the transformation of unspecialized cells into specialized cells that perform specific functions.

2. **Loss of End Walls**:
- During differentiation, some plant cells lose their end walls. This modification is significant in certain types of cells, such as sieve elements in the phloem, which allows for the efficient transport of nutrients.

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