The formation of micelles takes place above a particular concentration called………..

Explanation

To answer the question regarding the formation of micelles, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding Micelles**: Micelles are aggregates of surfactant molecules that form in a solution. They consist of a hydrophilic (water-attracting) "head" and a hydrophobic (water-repelling) "tail."

2. **Concentration of Surfactants**: The formation of micelles occurs when the concentration of surfactant molecules in the solution reaches a certain level. Below this level, surfactants exist primarily as individual molecules.

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