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