Echinoderms
Purpuratus
Animalia
Strongylocentrotus
Subtidal area only
Intertidal area only
Both intertidal area and subtidal areas
On the beach
Pentamerous
Dome
Toothpick
Porcupine
Feet
Spine
Mouth
Nose
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