What is the function of inner cell mass?

Answer

### Step-by-Step Solution:

1. **Definition of Inner Cell Mass**: The inner cell mass (ICM) is a group of cells located within the blastula, which is an early stage of embryonic development.

2. **Formation of the Blastula**: The blastula is formed during the cleavage stage of embryonic development, where the fertilized egg divides multiple times, resulting in a hollow structure known as the blastocoel.

3. **Composition of the Inner Cell Mass**: The inner cell mass typically consists of 6 to 10 cells that are crucial for the development of the embryo.

4. **Function of the Inner Cell Mass**: The primary function of the inner cell mass is to develop into the various parts of the embryo. It differentiates into three germ layers:
- **Endoderm**: This layer will form internal structures such as the digestive tract and respiratory system.
- **Mesoderm**: This layer contributes to the formation of muscles, bones, and the circulatory system.
- **Ectoderm**: This layer develops into the skin and nervous system.

5. **Cell Determination**: The cells within the inner cell mass are determined in terms of their fate, meaning they are pre-programmed to develop into specific structures of the embryo. For example, certain cells will develop into the brain, while others will form limbs or facial features.

6. **Conclusion**: The inner cell mass plays a critical role in the early stages of embryonic development by giving rise to the essential structures and layers that will form the complete organism.