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