What type of stoichiometric defect is shown by:
(a) `ZnS` (b) `AgBr`

Explanation

To determine the type of stoichiometric defects shown by ZnS and AgBr, we need to analyze each compound based on their crystal structures and the nature of their defects.

### Step-by-Step Solution:

1. **Understanding Stoichiometric Defects**:
- Stoichiometric defects are imperfections in the crystal lattice that do not alter the overall stoichiometry of the compound. The two main types of stoichiometric defects are Frenkel defects and Schottky defects.

2. **Analyzing ZnS**:
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