The outer layer of the sponge is covered by flattened cells that sometimes contract in response to potentially harmful stimuli to protect the inner cells of the sponge. One type of inner cells are , flagellated and collared cells that help circulate water through the sponge and collect food particles. Various types of cells are found in the mesohyl and may secrete structural components such as spicules or spongin fibers

Group control group #1 experimental group yes yes yes control group #2 no new drug orange juice bed rest no yes no yes ves which of the following is the best explanation of why a second control group was included in this experiment? o a. to provide the volunteers in the study with something to drink o b. to prove that the common cold cannot be cured c. to confuse anyone who is trying to steal their new drug and sell it as their own invention o d. to researchers conclude that results are related to the new drug and not to the orange juice submit e previous