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