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