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