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