What is the name and function of this structure?
Tube feet - used to circulate blood
Spines - used to protect the animal
Tube feet - used for animal movement and food capture
Madreporite - used to circulate water

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b