Why is SCID called primary immunodeficiency?

Explanation

### Step-by-Step Solution:

1. **Understanding SCID**:
- SCID stands for Severe Combined Immunodeficiency Disease. It is a genetic disorder that severely affects the immune system.

2. **Immune System Components**:
- The immune system comprises various cells, primarily B cells and T cells. B cells are responsible for producing antibodies, while T cells play a crucial role in directly killing pathogens and helping B cells function.

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