From which germ layers do the following organs differentiate?
(a) Kidney
(b) Urinary bladder.

Explanation

To answer the question regarding the germ layers from which the kidney and urinary bladder differentiate, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding Germ Layers**:
- There are three primary germ layers in embryonic development: ectoderm, mesoderm, and endoderm.
- The ectoderm is the outermost layer, forming structures like skin and nervous tissue.
- The mesoderm is the middle layer, responsible for forming muscles, bones, and connective tissues.
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