A body cavity is a space between the gut tube (lined with endoderm) and the body wall (with its outer covering of ectoderm). Such a body cavity, or coelom, can be formed in two ways. A true coelom is formed within the mesoderm layer; thus, the true coelom is entirely lined with mesoderm.

Coelom is formed between ectoderm and endoderm in the division of between them

Coelom is the cavity found between the Ectoderm and Endoderm.

Coelom is a fluid-filled body cavity that is lined by mesoderm. It is present in triploblastic organisms, which have three germ layers - ectoderm, mesoderm, and endoderm. The coelom is an important feature of advanced organisms as it provides a space for the development and protection of internal organs.

Explanation:

1. Definition of Coelom:
Coelom is a fluid-filled cavity that is completely lined by mesoderm. It is present in many bilateral animals, including vertebrates and most invertebrates. The coelom separates the body wall from the internal organs and provides a space for the organs to move and function independently.

2. Germ Layers:
During embryonic development, the three germ layers - ectoderm, mesoderm, and endoderm - are formed. The ectoderm gives rise to the outer layer of the skin and nervous system, the endoderm gives rise to the lining of the digestive tract, and the mesoderm gives rise to the muscles, skeleton, circulatory system, and reproductive organs.

3. Formation of Coelom:
The coelom is formed during the early stages of embryonic development. It arises from a cavity called the archenteron, which is formed during gastrulation when the cells invaginate and form a hollow tube. The mesoderm then splits into two layers, the somatic mesoderm and the splanchnic mesoderm, which surround the archenteron and form the coelom.

4. Location of Coelom:
In triploblastic organisms, the coelom is located between the ectoderm and endoderm. The ectoderm forms the outermost layer of the body, while the endoderm forms the innermost layer. The mesoderm, which gives rise to the coelom, is located between these two layers.

5. Functions of Coelom:
The coelom serves several important functions in organisms. It acts as a cushioning and protective layer for internal organs, allowing them to move and function independently. It also provides a space for the circulation of fluids, such as blood or hemolymph, which transport nutrients, gases, and waste products throughout the body. Additionally, the coelom acts as a hydrostatic skeleton, providing support and structure to the body.

In conclusion, the coelom is a fluid-filled cavity that is located between the ectoderm and endoderm. It is lined by mesoderm and plays a crucial role in providing space for organ development, protection, circulation, and support in triploblastic organisms.