1. PESTY POISONS

Many farmers use pesticides to kill insects that damage their crops. Unfortunately, these pesticides often harm birds and other animals. Pesticides also contaminate water supplies.

YOUR CHALLENGE: Invent a safer way to control crop-eating insects.

2. FISH KILLS

Many people use explosives and poisons to catch reef fish. In many cases, more fish are killed than needed And in most areas, many reef animals are also killed by the explosives and poison.

YOUR CHALLENGE: Invent a safer way to fish.

3. LIVESTOCK DAMAGE

Livestock, such as sheep, goats, and pigs, have been introduced to many tropical islands. The livestock roam the steep hillsides, eating much of the vegetation and loosening the soil with their hooves. Heavy rains wash the soils and manure from the denuded land into rivers and other bodies of water. The manure and silt pollute fragile aquatic habitats where young fish and other marine and freshwater creatures grow up. As a result, the number of fish in some areas has decreased.

YOUR CHALLENGE: Invent ways to avoid the siltation and pollution caused by livestock.

4 TRAFFIC TROUBLES

In many cities around the world, cars are the major means of transportation. They're also one of the major causes of air pollution. With so many people driving their cars every day, there's a lot of traffic. A great deal of air pollution is created by cars while they're stuck in traffic.

YOUR CHALLENGE: Invent a better form of transportation that's appropriate for your area.

5. CRUSHING CORALS

Coral reefs are a favorite place for scuba divers, snorkelers, sailors, and people who fish. All of these people take boats across the water and drop anchor above the reef. But these anchors often damage the coral, particularly when they've been set improperly, so that hey drag along the sea bottom as the boat drifts. In some popular scuba and fishing spots, damage from anchors has become a significant threat to the beauty and survival of the coral reef.

YOUR CHALLENGE: Invent a way to decrease the damage from the small ships anchoring at a coral reef.

6. OVER-PACKAGING

Bongos are tasty snack foods that are packaged in handy, single-sized servings. But once the snacks are eaten people toss the plastic wrappers away. Most of the wrappers end up in dumps that are already overflowing. And many toxic by-products are created when plastic is manufactured or burned.

YOUR CHALLENGE: Invent a better way to package Bongos and other snack foods.

7. GHOST FISHING

Nets mad of plastic are causing problems for marine animals. Unlike nets made of cotton, manila rope, or other natural fibers that disintegrate in a matter of months, plastic nets are very durable and can last for years and years.

That makes net mending less of a chore for fishers. But it has caused another big problem: ghost fishing. Nets and fishing line are frequently lost when people fish or travel. After a plastic net is lost, it can continue trapping fish - for years. "Ghost fishing" nets can trap seals, sea lions, dolphins, seabirds, and fish. One mile-wide ghost fishing net found in the North Pacific had trapped 99 seabirds that had tried to eat the fish already snared in the net.

YOUR CHALLENGE: Invent a way to fish efficiently without contributing to the ghost fishing problem.