What king of skin do sponges have?

Sponges have a unique body structure rather than traditional skin. Their outer layer, called the pinacoderm, is composed of flat cells known as pinacocytes, which provide protection and maintain the sponge's shape. Beneath this layer, sponges have a gelatinous substance called mesohyl, containing cells that perform various functions, including nutrient transport and structural support. Overall, sponges lack true tissues and organs, making their body structure distinct from that of more complex animals.