Purpuratus
Strongylocentrotus
Echinoderms
Animalia
Nose
Spine
Mouth
Feet
Pentamerous
Dome
Porcupine
Toothpick
Subtidal area only
On the beach
Intertidal area only
Both intertidal area and subtidal areas
Small fish
Sea cucumbers
Algae
Other sea urchins
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
Because sea urchins have large numbers of eggs