Experts please answer

Dear student,

Gastrulation takes place after cleavage and results in the formation of the three germ layers 

• Ectoderm - which gives rise to the neural tissues and the epidermis
• Mesoderm - which gives rise to the dermis, skeletal and muscle tissues, notochord, blood vessels and connective tissues
• Endoderm - which gives rise to the epithelial tissues of the respiratory and digestive systems and also digestive organs such as liver and the pancreas.   

Coelom:  The body of some animals is made up of three layers of cells, the outer ectoderm, the middle mesoderm and the inner endoderm. The body cavity or the coelom is the space enclosed by the mesoderm where the internal organs are suspended.

Acoelomates: Animals that have no body cavity are known as acoelomate. Example: flatworms

Pseudocoelomate: Some animals do not have a true coelom but the mesoderm is present in scattered pouches. Such animals are said to be pseudocoelomate. For example Phylum Nematoda. 

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