4 Written questions
3 Multiple choice questions
- They lack tissues, organs, and organ system.
- Gas exchange and excretion occur via diffusion across individual cell membranes.
- In simple sponges, water enter the body through pores in the walls called ostia and passes into the spongocoel, a central space lined with choanocytes where food particles are trapped and digested intracellulary. Nutrients are passed to neighboring cells. Water leaves through a hole at the top of the sponge called the osculum. In more complex body plans, there is no spongocoel but several smaller chambers lined with choanocytes
3 True/False questions
• Number of tissue → no body cavity
What is the sponge body comprised of? → The sponge body is comprised of a couple different cell types that form the outside and inside layers of the body wall.
What are choanocytes? → They lack tissues, organs, and organ system.