Feet
Nose
Mouth
Spine
Other sea urchins
Algae
Small fish
Sea cucumbers
On the beach
Both intertidal area and subtidal areas
Subtidal area only
Intertidal area only
Echinoderms
Animalia
Strongylocentrotus
Purpuratus
Porcupine
Pentamerous
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