What are the features of Class Demospongiae? A. small and dull in color with a skeleton make of calcium
carbonate
B. can be up to 6 ft. in length and used as natural bath sponges
C. "glass sponges" made from silica

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

d. changes in climate and historical records

hope this