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