Co-enzyme can function in association with an apoenzyme.

Explanation

### Step-by-Step Solution:

1. **Understanding Enzymes**: Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are primarily made of proteins.

2. **Defining Apoenzyme**: The protein part of an enzyme is referred to as the apoenzyme. This is the inactive form of the enzyme that requires a non-protein component to become active.

3. **Role of Cofactors**: Enzymes require additional non-protein molecules known as cofactors for their activity. Cofactors can be either organic or inorganic.

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