Which animal phylum lacks true tissues?

Which animal phylum lacks true tissues?

• A. Porifera
• B. Cnidaria
• C. Platyhelminthes
• D. Nematoda

Answer: (A)

The main idea here is understanding tissue organization in animals. A true tissue is a coordinated group of similar cells that work together and arise from embryonic germ layers. Sponges lack this level of organization. Their bodies are built from individual cells embedded in a jelly-like matrix, with specialized cells like choanocytes carrying out feeding and other functions, but there are no integrated tissue layers or organs formed. Because they don’t develop tissues from germ layers, they’re organized at the cellular level rather than into tissues. By contrast, other listed animals do have true tissues; cnidarians have two true tissue layers, and the other two groups show even more advanced tissue and organ development. So this phylum is the one that lacks true tissues.

The main idea here is understanding tissue organization in animals. A true tissue is a coordinated group of similar cells that work together and arise from embryonic germ layers. Sponges lack this level of organization. Their bodies are built from individual cells embedded in a jelly-like matrix, with specialized cells like choanocytes carrying out feeding and other functions, but there are no integrated tissue layers or organs formed. Because they don’t develop tissues from germ layers, they’re organized at the cellular level rather than into tissues. By contrast, other listed animals do have true tissues; cnidarians have two true tissue layers, and the other two groups show even more advanced tissue and organ development. So this phylum is the one that lacks true tissues.