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