Why don’t force pairs have equal effects?

Which entry is in the wrong position in the table?

What type of appendages do sponges cnidarians roundworms annelids mollusks arthropods echinoderms and vertebrate have? jointed, not jointed, absent  

If you relate the doppler effect on sound to the color of light waves, a police car would be the color as it approaches and the color as it recedes away from the observer.