What are the key differences between a coelom and a pseudocoelom in terms of their structure and function within the body cavity of organisms?

The key difference between a coelom and a pseudocoelom lies in their structure and function within the body cavity of organisms. A coelom is a true body cavity that is completely lined with mesoderm tissue, providing support and protection for internal organs. In contrast, a pseudocoelom is a body cavity that is only partially lined with mesoderm tissue, resulting in less structural support for organs. Functionally, the coelom allows for more efficient movement and protection of organs, while the pseudocoelom may provide some support but is less effective in this regard.