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