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