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