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 the eggs make great omlettes
Because sea urchins have large numbers of eggs
Because a sea urchin's egg is relatively big
Small fish
Other sea urchins
Algae
Sea cucumbers
Animalia
Echinoderms
Strongylocentrotus
Purpuratus
Nose
Feet
Spine
Mouth
Dome
Pentamerous
Porcupine
Toothpick