4 Written questions
3 Multiple choice questions
- They lack tissues, organs, and organ system.
- Extracellular protein fibers give structure and strength to the sponge body and spicules, spines made of silica or calcium carbonate, offer protection from predation.
- Gas exchange and excretion occur via diffusion across individual cell membranes.
3 True/False questions
How does water enter the body? → 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
What are choanocytes? → Specialized flagellated cells, choanocytes, move water through and filter food particles from the water
what kind of digestion? → Sponges are sessile (sedentary), filter feeding animals