Three primary germ layers of gastrula are ectoderm............... and..............

Explanation

To answer the question about the three primary germ layers of the gastrula, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the First Germ Layer**: The first germ layer mentioned in the question is **ectoderm**. This layer is the outermost layer of the gastrula.

2. **Identify the Second Germ Layer**: The second germ layer is **mesoderm**. This layer is located between the ectoderm and endoderm and is responsible for forming various tissues, including muscles and blood.

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