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