### Break Down the Problem
1. Identify the layers of cells formed after gastrulation in sea urchins.
2. Understand which layer remains on the surface.

### Relevant Concepts
- **Gastrulation**: A key phase in embryonic development that leads to the formation of three primary germ layers: ectoderm, mesoderm, and endoderm.
- **Cell Layers**:
- **Ectoderm**: The outermost germ layer which forms the skin and nervous system.
- **Mesoderm**: The middle germ layer that forms muscles, bones, and the circulatory system.
- **Endoderm**: The innermost germ layer that forms the gut and internal organs.
- **Blastocyst**: A structure formed in early embryonic development in mammals; not a layer in sea urchins.

### Analysis and Detail
After gastrulation, the ectoderm is the layer that remains on the surface of the embryo. As the mesoderm and endoderm are formed, the ectoderm continues to lie on the outermost part, giving rise to structures such as the epidermis and neural tissue.

### Verify and Summarize
The ectoderm is confirmed to be the surface layer, while mesoderm and endoderm are located internally in the embryo.

### Final Answer
**Ectoderm** is the correct answer.

Question

### Break Down the Problem
1. Identify the layers of cells formed after gastrulation in sea urchins.
2. Understand which layer remains on the surface.

### Relevant Concepts
- **Gastrulation**: A key phase in embryonic development that leads to the formation of three primary germ layers: ectoderm, mesoderm, and endoderm.
- **Cell Layers**:
  - **Ectoderm**: The outermost germ layer which forms the skin and nervous system.
  - **Mesoderm**: The middle germ layer that forms muscles, bones, and the circulatory system.
  - **Endoderm**: The innermost germ layer that forms the gut and internal organs.
  - **Blastocyst**: A structure formed in early embryonic development in mammals; not a layer in sea urchins.

### Analysis and Detail
After gastrulation, the ectoderm is the layer that remains on the surface of the embryo. As the mesoderm and endoderm are formed, the ectoderm continues to lie on the outermost part, giving rise to structures such as the epidermis and neural tissue.

### Verify and Summarize
The ectoderm is confirmed to be the surface layer, while mesoderm and endoderm are located internally in the embryo.

### Final Answer
**Ectoderm** is the correct answer.

Knowee AI · Accepted Answer

### Break Down the Problem
1. Identify the layers of cells formed after gastrulation in sea urchins.
2. Understand which layer remains on the surface.

### Relevant Concepts
- **Gastrulation**: A key phase in embryonic development that leads to the formation of three primary germ layers: ectoderm, mesoderm, and endoderm.
- **Cell Layers**:
  - **Ectoderm**: The outermost germ layer which forms the skin and nervous system.
  - **Mesoderm**: The middle germ layer that forms muscles, bones, and the circulatory system.
  - **Endoderm**: The innermost germ layer that forms the gut and internal organs.
  - **Blastocyst**: A structure formed in early embryonic development in mammals; not a layer in sea urchins.

### Analysis and Detail
After gastrulation, the ectoderm is the layer that remains on the surface of the embryo. As the mesoderm and endoderm are formed, the ectoderm continues to lie on the outermost part, giving rise to structures such as the epidermis and neural tissue.

### Verify and Summarize
The ectoderm is confirmed to be the surface layer, while mesoderm and endoderm are located internally in the embryo.

### Final Answer
**Ectoderm** is the correct answer.

After gastrulation in sea urchins, identify the cells that remain on the surface.Multiple choice question.MesodermEndodermEctodermBlastocyst

Question

After gastrulation in sea urchins, identify the cells that remain on the surface.

Solution

Break Down the Problem

Relevant Concepts

Analysis and Detail

Verify and Summarize

Final Answer

Similar Questions

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