Select the most appropriate ANTONYM of the underlined word.
The growth of the cell wall is very rarely uniform.

The correct option is Variegated.

Explanation:

In the given sentence, the underlined word "uniform" means remaining the same in all cases and at all times; consistent, even, or unvarying.

Let's analyze the meanings of the given options:

1. Fixed: Fastened securely; definite or permanent (Not an antonym of uniform in this context).

2. Paired: Arranged in pairs (Unrelated to uniform).

3. Balanced: Keeping or showing a balance; in good proportions (Synonymous/related to evenness rather than an opposite).

4. Variegated: Exhibiting different colors, patterns, or forms; varied, diverse, or irregular. This is the exact antonym of uniform.

Thus, Variegated is the most appropriate antonym of uniform.