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