Mouth
Feet
Spine
Nose
Both intertidal area and subtidal areas
On the beach
Subtidal area only
Intertidal area only
Animalia
Purpuratus
Strongylocentrotus
Echinoderms
Small fish
Sea cucumbers
Algae
Other sea urchins
Pentamerous
Porcupine
Toothpick
Dome
Because sea urchins have large numbers of eggs
Because the eggs make great omlettes
Because sea urchins have large numbers of relatively big eggs
Because a sea urchin's egg is relatively big