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