Select incorrect statement about mesenchyme:
Cellular and Gelatinous layer
Consists of spicules and amoeboid cells
Proteinaceous layer
Present in body wall of sponges
The body wall of a sponge, specifically in the phylum Porifera, is composed of two layers. The outer layer is known as the pinacoderm, while the inner layer is called the choanoderm. These layers enclose a non-cellular mesenchyme, which is an interconnecting proteinaceous gelatinous matrix. The mesenchyme provides structural support and connects the two layers of the sponge's body wall. Hence, the correct answer is option 1.