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