Insect wings are outgrowths of their exoskeleton rather than modified legs B35. Zebra mussels cause severe problems in lakes by stirring up bottom sediments and making the water very turbid. All leeches must take a blood meal before they can reproduce. Brainworms do not harm white-tailed deer, but they can kill moose. Coral reefs are highly productive and diverse despite being located in nutrient-poor waters A39.
Sponges lack a gut.
The typical diet of sponges includes small fish and crustaceans A41. Sponges are common in lakes and streams around Marquette A42. Tapeworms have no mouth or digestive tract B43. Clam shells are currently in high demand for making buttons B44. Most insects undergo a simple metamorphosis without any resting stage A45.