I read that animals have either bilateral symmetry or radial symmetry, the latter being like in starfish. However, even round animals have five of something in them I thought, and why aren’t four limbs and head considered five-ways symmetry? Thus all animals have pent-something symmetry. Or do they?
This would only be true if your head was equivalent to your arm or leg. “Symmetry” implies the components are exactly or almost exactly equivalent (except for mirror-image type reversal for bilateral organisms). A starfish’s arms are essentially alike.
Um, consider creatures like the centipede. Lotsa legs, so even if we considered all appendages the “same,” there would be no 5-way symmetry here.