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Grade 4 Reading Worksheet - Challenge Me
Read both texts. Circle which text gives each detail.
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Coral Reefs Under Pressure
Text 1: Coral Reefs, Built by Tiny Animals
Coral reefs look like rocks or plants, but they are built by animals. A coral is made of many tiny animals called polyps. Each polyp has a soft body and stinging arms. Many kinds of polyps build a hard skeleton of limestone around themselves. When polyps die, their skeletons stay behind, and new polyps grow on top. Over thousands of years, this slow work creates a reef.
Most reef-building corals live in warm, shallow, clear seas, where sunlight can reach them. Tiny algae live inside the polyps. The algae use sunlight to make food and share it with the polyp, and they also give coral its bright colors.
Reefs cover less than one percent of the ocean floor, yet about a quarter of all ocean animals spend part of their lives there. Fish hide among the branches, and crabs and shrimp search for food. The Great Barrier Reef, off the coast of Australia, is the largest reef system in the world. Reefs also protect coastlines. Their rough walls slow big waves before they reach the shore, which helps keep beaches from washing away.
Hot water is a serious danger. When the sea stays too warm for too long, polyps push out their algae and turn white. This is called bleaching. A bleached coral is not dead, but it is weak. If the water does not cool, the coral may starve.
Text 2: Coral Gardeners of the Florida Keys
Off the Florida Keys, Dr. Carla Duarte swims between rows of plastic pipes shaped like trees. From each branch hangs a small piece of staghorn coral, no longer than a finger. Divers snipped these pieces from healthy corals. The parent coral heals, and the small piece begins to grow. Every few weeks, divers clean the pipes so that seaweed does not cover the young coral. So far, her team has planted thousands of pieces on nearby reefs.
"Staghorn is one of the fastest-growing corals," says Dr. Duarte. "In a nursery, a piece can grow several inches in a year." After some months, divers carry the larger pieces to a damaged reef. They fasten each piece to the rock with a special cement, and it keeps growing there.
Dr. Duarte says the work has limits. "If the ocean stays too hot, even healthy corals will bleach," she explains. "Planting coral helps, but corals also need cooler, cleaner water."
Which text gives this detail? Reefs cover less than one percent of the ocean floor.
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Which text gives this detail? The Great Barrier Reef is the largest reef system in the world.
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Which text gives this detail? Water that stays too warm can make corals bleach.
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Which text gives this detail? Coral reefs are protected by laws in most countries.
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